CN105577053B

CN105577053B - Trigger and generator voltage regulator

Info

Publication number: CN105577053B
Application number: CN201610121417.2A
Authority: CN
Inventors: 杨明
Original assignee: Xi'an Zhicaiquan Technology Transfer Center Co ltd
Current assignee: Xi'an Silk Road Zhixing Technology Service Co ltd
Priority date: 2016-02-01
Filing date: 2016-03-03
Publication date: 2020-11-17
Anticipated expiration: 2036-03-03
Also published as: CN105703724A; CN105577053A; CN105703724B; CN105790659A; CN105790659B

Abstract

The invention provides a trigger and a voltage regulator of a generator, wherein the trigger comprises: the comparison unit is connected with a power supply end, the ground and the switch unit and is used for outputting a first voltage to the switch unit when the non-inverting input end is larger than the voltage of the inverting input end; outputting a second voltage to the switching unit when the non-inverting input terminal is smaller than the voltage of the inverting input terminal; the switch unit is connected with the ground or the positive electrode of the power supply and is also connected with the control end of the trigger and used for conducting the control end with the ground or conducting the control end with the positive electrode of the power supply under the control of the comparison unit; the feedback unit is connected with the control end and the inverting input end of the comparison unit and is used for positively feeding back a signal of the control end to the inverting input end of the comparison unit; when the trigger is applied to a voltage regulator, the multifunctional integration of fixed-frequency triggering excitation, overvoltage immediate cut-off and overcurrent protection is realized; the sampling circuit does not need to be provided with a capacitor, synchronous detection overvoltage is used for cutting off excitation, overtime overvoltage excitation is avoided, voltage is stable, adjustment is accurate, safety and reliability are achieved, and the service lives of the regulator and the generator are prolonged.

Description

Trigger and generator voltage regulator

Technical Field

The invention relates to the technical field of control, in particular to a trigger and a voltage regulator of a generator.

Background

The power supply of the automobile generally comprises a generator and a storage battery. The automobile generator is driven by the automobile engine to generate direct current or alternating current in the running process of the automobile so as to provide electric energy required by the automobile. Generally, an excitation ac generator is often used, in which the amount of generated power is controlled by an excitation coil, and a voltage regulator is correspondingly provided to cut off the excitation current on the coil when the output voltage of the generator (i.e., the voltage output by the positive electrode of the power supply) is higher than a set threshold voltage.

However, the existing voltage regulator for the generator of the automobile (hereinafter referred to as voltage regulator) has the following three problems, which are specifically described as follows:

(1) the voltage regulator usually adopts a plurality of resistors connected in series as sampling resistors, and then controls the power tube to cut off the exciting current through a post-stage circuit. In order to adjust the excitation frequency and improve the excitation current waveform of the power tube, a filter capacitor needs to be connected to the sampling resistor. The filter capacitor and the sampling resistor form an RC (resistor-capacitor) network, so that the change of the signal voltage on the sampling node lags behind the real-time working condition of the generator, and a delay exists between the time point when the voltage of the generator exceeds the threshold voltage and the time point when the exciting current is cut off, namely the regulator, the exciting coil and the generator always work in an exciting state within the delay. Although the delay time is short, the delay time corresponds to a larger electrical angle, so that the generator works in an overvoltage excitation state which should not occur, particularly, a larger current and even a larger load rejection voltage can be caused at a high speed, thereby threatening regulators and other electrical equipment, and the generator of the automobile, particularly the voltage regulator, can be damaged early in the long term, and reducing the service life; most of the existing voltage regulators are triggered in a non-fixed frequency mode, so that the instability of output voltage and high ripple coefficient are brought; in addition, the edge of the excitation waveform output by the existing voltage regulator is not steep and has more clutter, so that the loss of the device is large, the temperature is increased, the device is easy to damage, and the service life is shortened;

(2) the trigger in the existing voltage regulator, especially the fixed frequency excitation circuit, has the disadvantages of complex structure, difficult realization, high cost, large volume and much heat generation, and influences the performance of the whole generator;

(3) because the automobile generator runs in a high-temperature severe environment, the leakage and short-circuit failure rate caused by the rotor and the carbon brush of the automobile generator is high, the power tube in the regulator is easy to generate the condition of overcurrent damage, and an overcurrent protection circuit is required to be arranged for protection. However, the current overcurrent protection circuit has the disadvantages of overlong overcurrent peak time, delayed protection action, complex circuit, more heat generation, unstable and inaccurate protection start control time, so that even if the overcurrent protection circuit is arranged, the power tube is still easily damaged due to overcurrent, and the service life of the regulator is shortened.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a flip-flop is provided which, when applied to a voltage regulator, solves at least one of the above-mentioned problems.

To achieve the above object, the present invention provides a trigger and a voltage regulator for a generator.

According to a first aspect of the present invention, there is provided a flip-flop comprising a comparing unit, a switching unit and a feedback unit;

the comparison unit is connected with the switch unit and used for outputting a first voltage to the switch unit when the non-inverting input end is larger than the voltage of the inverting input end; outputting a second voltage to the switching unit when the non-inverting input terminal is smaller than the voltage of the inverting input terminal;

the switch unit is connected with the anode of the ground or the power supply and is also connected with the control end of the trigger and used for conducting the control end with the anode of the ground or the power supply under the control of the comparison unit;

the feedback unit is connected with the control end and the inverting input end of the comparison unit and is used for feeding back a signal of the control end to the inverting input end of the comparison unit;

the feedback unit is a positive feedback unit and comprises an overcurrent protection circuit, and the overcurrent protection circuit is used for performing overcurrent protection on the switch unit through the comparison unit.

According to a second aspect of the present invention, there is provided a second flip-flop, comprising a switch control unit, a switch unit and a feedback unit;

the switch control unit is connected with the switch unit and used for outputting a third voltage to the switch unit when the switch unit is switched on and outputting a fourth voltage to the switch unit when the switch unit is switched off;

the switch unit is connected with the anode of the ground or the power supply and is also connected with the control end of the trigger, and the control end is conducted with the anode of the ground or the power supply under the control of the switch control unit;

the feedback unit is connected with the control end and the input end of the switch control unit and is used for feeding back a signal of the control end to the input end of the switch control unit;

the feedback unit is a positive feedback unit and comprises an overcurrent protection circuit, and the overcurrent protection circuit is used for performing overcurrent protection on the switch unit through the switch control unit.

According to a third aspect of the present invention, there is provided a third flip-flop, comprising a comparing unit, a switching unit and a feedback unit;

the feedback unit is connected with the control end and the in-phase input end of the comparison unit and is used for feeding back a signal of the control end to the in-phase input end of the comparison unit;

According to a fourth aspect of the present invention, there is provided a voltage regulator for a generator, comprising a first type of trigger.

Preferably, the voltage regulator further comprises a follow current unit, a voltage stabilizing unit, a sampling unit, an error comparing and amplifying unit, an oscillating unit, a shaping unit and a reference threshold setting unit;

the follow current unit is connected with the positive electrode of the power supply and the switch unit, and is used for forming a loop with a load connected between the control end of the trigger and the positive electrode of the power supply and absorbing induced electromotive force generated by the load; the voltage stabilizing unit is connected with the power supply anode, the ground, the reference threshold setting unit, the comparing unit and the oscillating unit and is used for providing stable voltage for the reference threshold setting unit and the comparing unit; the sampling unit is connected with the positive electrode of the power supply, the ground and the non-inverting input end of the error comparing and amplifying unit and is used for providing sampling voltage for the non-inverting input end of the error comparing and amplifying unit; the reference threshold setting unit is connected with the inverting input end of the error comparison amplifying unit, the ground and the non-inverting input end of the comparing unit, and is used for providing a first threshold voltage for the inverting input end of the error comparison amplifying unit and providing a second threshold voltage for the non-inverting input end of the comparing unit; the output end of the error comparison amplification unit is connected with the comparison unit and used for providing a first voltage for the inverting input end of the comparison unit when the voltage of the non-inverting input end of the error comparison amplification unit is greater than the inverting input end, wherein the first voltage is greater than a second threshold voltage, so that the trigger is reset to be in a cut-off state of the switch unit and self-locked under the trigger of the first voltage, and the excitation current of the generator is cut off; the oscillating unit is connected with the ground and the shaping unit, the shaping unit is connected with the in-phase input end of the comparison unit, the oscillating unit inputs narrow pulses to the in-phase input end of the comparison unit under the action of the shaping unit, the trigger is set to be in a switch unit conduction state and self-locked under the trigger of the narrow pulses, and the excitation current of the generator is switched on.

According to a fifth aspect of the present invention, there is provided a voltage regulator of a generator, comprising a second type of trigger.

Preferably, the follow current unit is connected with the positive electrode of the power supply and the switch unit; the first voltage stabilizing unit is connected with the positive electrode of the power supply, the ground, the switch control unit and the oscillating unit and is used for providing stable voltage for the switch control unit and the oscillating unit; the sampling unit is connected with the positive electrode of the power supply, the ground and the second voltage stabilizing unit, the second voltage stabilizing unit is connected with the input end of the switch control unit, and the sampling unit provides an overvoltage signal for the input end of the switch control unit under the voltage stabilizing effect of the second voltage stabilizing unit, so that the trigger is reset to be in a cut-off state of the switch unit and is self-locked under the triggering of the overvoltage signal, and the excitation current of the generator is cut off; the oscillating unit is connected with the ground and the shaping unit, the shaping unit is connected with the input end of the switch control unit, the oscillating unit inputs narrow pulses to the switch control unit under the action of the shaping unit, the trigger is set to be in a switch unit conducting state and self-locked under the trigger of the narrow pulses, and the excitation current of the generator is switched on.

Preferably, the voltage regulator further comprises a freewheeling unit, a third voltage stabilizing unit, a fourth voltage stabilizing unit, a sampling unit, an oscillating unit and a shaping unit;

the follow current unit is connected with the negative electrode of the power supply and the switch unit; the third voltage stabilizing unit is connected with the positive electrode of the power supply, the ground, the oscillating unit and the output end of the switch control unit and is used for providing stable voltage for the oscillating unit and the switch control unit; the sampling unit is connected with the positive electrode of the power supply, the ground and the fourth voltage stabilizing unit and is used for providing an overvoltage signal for the input end of the switch control unit under the voltage stabilizing effect of the fourth voltage stabilizing unit, so that the trigger is reset and self-locked under the triggering of the overvoltage signal, and the excitation current of the generator is cut off; the oscillating unit is connected with the ground and the shaping unit, the shaping unit is connected with the input end of the switch control unit, the oscillating unit inputs narrow pulses to the switch control unit under the action of the shaping unit, the trigger is set to be in a switch unit conducting state and self-locked under the trigger of the narrow pulses, and the excitation current of the generator is switched on.

According to a sixth aspect of the present invention, there is provided a voltage regulator of a generator, comprising a third type of trigger.

Preferably, the voltage regulator further comprises a freewheeling unit, a fifth voltage stabilizing unit, a sixth voltage stabilizing unit, a sampling unit, an oscillating unit, a shaping unit and a reference threshold setting unit;

wherein the follow current unit is connected with the ground and the switch unit; the fifth voltage stabilizing unit is connected with the positive electrode of the power supply, the ground, the oscillating unit, the reference threshold setting unit and the comparing unit and is used for providing stable voltage for the oscillating unit, the reference threshold setting unit and the comparing unit; the sampling unit is connected with the positive electrode of the power supply, the ground and the sixth voltage stabilizing unit and is used for providing an overvoltage signal for the in-phase input end of the comparing unit under the action of the sixth voltage stabilizing unit, so that the trigger is reset and self-locked under the trigger of the overvoltage signal, and the excitation current of the generator is cut off; the reference threshold setting unit is connected with the positive electrode of the power supply and the inverting input end of the comparing unit and is used for providing a second threshold voltage for the non-inverting input end of the comparing unit; the oscillating unit is connected with the positive electrode of the power supply and the shaping unit, the shaping unit is connected with the inverting input end of the comparing unit, the oscillating unit inputs narrow pulses to the inverting input end of the comparing unit under the action of the shaping unit, the trigger is set to be in a switch unit conducting state and self-locked under the trigger of the narrow pulses, and the excitation current of the generator is switched on.

Preferably, the voltage regulator further comprises a freewheeling unit, a voltage stabilizing unit, a sampling unit, an oscillating unit, a shaping unit and a reference threshold setting unit;

the follow current unit is connected with the positive electrode of the power supply and the switch unit; the voltage stabilizing unit is connected with the positive electrode of the power supply, the ground, the reference threshold setting unit, the oscillating unit and the comparing unit and is used for providing stable voltage for the reference threshold setting unit, the oscillating unit and the comparing unit; the reference threshold setting unit is connected with the in-phase input end of the comparison unit and is used for providing a first threshold voltage for the in-phase input end of the comparison unit; the sampling unit is connected with the positive pole of the power supply, the ground and the inverting input end of the comparison unit, so that the trigger is reset to be in a cut-off state of the switch unit and self-locked when the sampling voltage is greater than the first threshold voltage, and the excitation current of the generator is cut off; the oscillating unit is connected with the ground and the shaping unit, the shaping unit is connected with the input end of the switching unit, and the oscillating unit inputs narrow pulses to the switching unit under the action of the shaping unit, so that the trigger is set to be in a switching unit conducting state under the trigger of the narrow pulses and is self-locked to switch on the excitation current of the generator; and a current limiting resistor is also connected in series between the comparison unit and the switch unit and is used for limiting the current of the output end of the comparison unit.

The trigger and the automobile voltage regulator applying the trigger provided by the invention have the following beneficial effects:

(1) the trigger provided by the invention comprises a comparison unit (or a switch control unit), a switch unit and a feedback unit. When the trigger is applied to the voltage regulator, a filter capacitor does not need to be arranged in a sampling circuit, so that after the voltage of the excitation coil exceeds the threshold voltage, the trigger can turn over to cut off the excitation current and carry out self-locking, the excitation cut-off has no time delay, the automobile generator, particularly the voltage regulator, is not easy to be damaged too early, and the service life of the generator is prolonged. Meanwhile, the voltage division node of the sampling circuit has no capacitor, and the voltage transient amplitude on the node is not reduced by compression, so that the adjustment precision is improved, and the safety and reliability of the automobile generator are effectively guaranteed.

Meanwhile, the trigger provided by the invention is applied to a voltage regulator of an automobile generator, and excitation is regulated at a fixed frequency during normal regulation, so that voltage fluctuation is reduced, and output voltage is more stable. The constant frequency excitation can also make the electromagnetic resistance of the generator uniform, the fluctuation of the rotating speed is small, the belt and the gear train bearing are stressed in a balanced way, the service life is prolonged, the idling stability of the engine is improved, the combustion is improved, the fuel is saved, and the emission is reduced. The ripple coefficient of the output voltage of the generator can be reduced, the power supply environment of the electric equipment on the vehicle, particularly a microelectronic control circuit, is improved, and the electromagnetic interference scattered by a charging circuit of the generator can be reduced.

In addition, the excitation waveform of the trigger provided by the invention is not interfered by clutter on a sampling signal, the power tube is rapidly turned over, and the power tube is not retained in an amplification area. And the temperature rise is low, the safety is high, and the service life is long.

(2) The trigger provided by the invention has small occupied area and low cost, and can adopt a double transistor or a transistor array, so that the consistency of the tube is further improved, and the volume is reduced. And the temperature resistance is good, when the voltage regulator is formed by discrete devices or special integrated chips, the voltage regulator can reach an excellent working temperature index of resisting the temperature of 150 ℃ or above, and can meet the harsh working environment temperature requirement of the generator on the regulator, thereby realizing the voltage regulator with the fixed-frequency excitation function of excitation cut-off without delay of a protection circuit by using the discrete devices with higher temperature resistance. In addition, the trigger provided by the invention has strong stability, the integral trigger structure with comprehensive functions is adopted to improve the stability of the whole function of the circuit, and the trigger adopts a hardware circuit and has the advantages of strong surge impact resistance, strong interference resistance, strong stability, high reliability and the like.

(3) The trigger provided by the invention has the overcurrent protection function, and when the power tube is in overcurrent such as short circuit of a load, the trigger is immediately overturned through the strong positive feedback function of the feedback unit in the trigger, and the power tube is immediately cut off and is self-locked in a cut-off state. Because the more serious the short circuit is, the steeper the voltage peak is, the shorter the overcurrent time is, and under the action of the overcurrent protection circuit, the time required by the trigger from the occurrence of the short circuit or the overcurrent to the reliable cut-off of the power tube is only the flip time of the trigger, generally from a few nanoseconds to tens of nanoseconds, so that the phenomenon that the power tube is overheated because the original steep overvoltage peak is pulled down by a capacitor of a locking circuit is avoided, the conducting time of the power tube is extremely short in the overcurrent period, the overheating phenomenon of the power tube cannot occur even if the short circuit is continuously performed for a long time, and the protection of the power tube is safer and more reliable.

In addition, the trigger provided by the invention can also be applied to other control circuits such as electromagnetic coil load, resistive load, motor load and the like, and has a sensitive and reliable overcurrent protection function of the power tube.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram of a first flip-flop according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a second flip-flop according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a third flip-flop according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a voltage regulator including a first type of flip-flop according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a voltage regulator including a second type of flip-flop according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a voltage regulator including a second type of flip-flop according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a voltage regulator including a third flip-flop according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of another voltage regulator including a third flip-flop according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The embodiment of the invention provides a trigger and a voltage regulator of a generator, and the trigger provided by the invention is firstly explained with reference to the attached drawings.

In a first aspect, as shown in fig. 1, fig. 1 illustrates a first flip-flop provided in an embodiment of the present invention, which includes a comparing unit 1, a switching unit 2, and a feedback unit 3.

The comparison unit 1 is connected with the switch unit 2 and used for outputting a first voltage to the switch unit 2 when the non-inverting input end is larger than the voltage of the inverting input end; outputting a second voltage to the switch unit 2 when the non-inverting input terminal is less than the voltage of the inverting input terminal; the switch unit 2 is connected to ground and also connected to a control terminal (i.e., terminal F in fig. 1) of the flip-flop, and is configured to conduct the terminal F to ground under the control of the comparison unit 1; the feedback unit 3 is connected with the F end and the inverting input end of the comparison unit 1 and is used for feeding back a signal of the F end to the inverting input end of the comparison unit 1; the feedback unit 3 constitutes a positive feedback unit of the comparing unit 1 and the switching unit 2, so that the flip-flop can have two stable states, namely a set state in which the switching unit 2 is turned on and an off state of the switching unit 2. In addition, the feedback unit 3 further includes an overcurrent protection circuit for performing overcurrent protection on the power tube in the switch unit 2.

In a second aspect, as shown in fig. 2, fig. 2 shows a second trigger provided in the embodiment of the present invention, which includes a switch control unit 4, a switch unit 2, and a feedback unit 3.

The switch control unit 4 is connected with the switch unit 2 and is used for outputting a third voltage to the switch unit 2 when the switch unit is switched on and outputting a fourth voltage to the switch unit 2 when the switch unit is switched off; the switch unit 2 is connected to ground and also connected to a control terminal (i.e., terminal F in fig. 2) of the trigger, and is configured to conduct the terminal F to ground under the control of the switch control unit 4; the feedback unit 3 is connected with the F terminal and the input terminal of the switch control unit 4, and is used for feeding back a signal of the F terminal to the input terminal of the switch control unit 4; the feedback unit 3 forms a positive feedback unit of the switch control unit 4 and the switch unit 2, so that the trigger can have two stable states, namely a set state in which the switch unit 2 is turned on and a reset state in which the switch unit 2 is turned off. In addition, the feedback unit 3 further includes an overcurrent protection circuit for performing overcurrent protection on the power tube in the switch unit 2.

In a third aspect, as shown in fig. 3, fig. 3 shows a third flip-flop provided in the embodiment of the present invention, which includes a comparing unit 1, a switching unit 2, and a feedback unit 3;

the comparison unit 1 is connected with the switch unit 2 and used for outputting a first voltage to the switch unit 2 when the non-inverting input end is larger than the voltage of the inverting input end; outputting a second voltage to the switch unit 2 when the non-inverting input terminal is less than the voltage of the inverting input terminal; the switch unit 2 is connected to ground and also connected to a control terminal (i.e., terminal F in fig. 3) of the flip-flop, and is configured to conduct the terminal F to ground under the control of the comparison unit 1; the feedback unit 3 is connected with the F end and the in-phase input end of the comparison unit 1 and is used for feeding back a signal of the F end to the in-phase input end of the comparison unit 1; the feedback unit 3 constitutes a positive feedback unit of the comparing unit 1 and the switching unit 2, so that the trigger can have two stable states, namely a set state in which the switching unit 2 is turned on and a reset state in which the switching unit 2 is turned off.

It should be noted that, the switch unit in the three types of flip-flops may further be connected to the positive electrode of the power supply and the control terminal of the flip-flop, and is configured to conduct the terminal F and the positive electrode of the power supply under the control of the comparing unit (or the switch control unit of the second type of flip-flop). Other connection modes and functions are unchanged.

In practical implementation, each unit of the three types of flip-flops can be implemented in various ways. The following examples are given.

For example, the first type of flip-flop may be the structure shown in fig. 1. The comparison unit 1 may be a comparator, and the output end thereof is connected with the switch unit 2; the switch unit 2 may be a power transistor, and has a source connected to ground and a drain connected to the terminal F. When the power tube is switched on, the voltage at the F end is pulled down, and when the power tube is switched off, the voltage at the F end is pulled up by an external load. The feedback unit 3 is a positive feedback unit, and is configured to feed back the signal at the F terminal to the inverting input terminal of the comparing unit 1 with the signal polarity of the positive feedback.

For example, the second type of flip-flop may be configured as shown in FIG. 2. The switch control unit 4 may include a resistor and a switching tube connected in series; the switch unit 2 may be a power tube, the source electrode of which is grounded, the drain electrode of which is connected to the F terminal, and the power tube pulls the F terminal voltage low when it is turned on and pulls the F terminal voltage high when it is turned off. Furthermore, the feedback unit 3 may comprise a resistor and an anti-parallel diode (not shown in fig. 2) connected in series for feeding back the signal at the F terminal to the input terminal of the switch control unit 4 with a positive feedback signal polarity.

For example, the third type of flip-flop may be configured as shown in FIG. 3. The comparison unit 1 may be a comparator, and the output end thereof is connected with the switch unit 2; the switch unit 2 may be a power transistor, and has a source connected to ground and a drain connected to the terminal F. When the power tube is switched on, the voltage of the F end is pulled down, and when the power tube is switched off, the voltage of the F end is pulled up. The feedback unit 3 may be a positive feedback unit, and is configured to positively feed back the signal at the F terminal to the non-inverting input terminal of the comparator.

It is understood that the three specific structures of the flip-flop are just three examples for better illustration of the flip-flop of the present invention. In practical applications, the specific structures of the three flip-flops provided by the present invention may be modified appropriately according to different situations, and the present invention is not limited to this. Any trigger structure that can realize the three trigger functions is within the protection scope of the present invention.

The embodiment of the invention provides the three triggers, and when the three triggers are applied to a voltage regulator, a capacitor is not needed in a sampling circuit of the regulator to correct the excitation frequency and the excitation waveform. When the output voltage of the generator is detected to be increased to the threshold voltage, the excitation current can be immediately triggered and cut off, overvoltage excitation is not generated, the automobile generator and the voltage regulator are not prone to being prematurely damaged, and the service lives of the regulator and the generator are prolonged. The trigger provided by the invention has the advantages of small occupied area, strong stability and good temperature resistance, and can meet the harsh working environment temperature requirement of the generator on the unit regulator. In addition, the trigger provided by the invention has a simple and reliable overcurrent protection circuit, when the power tube is in overcurrent such as load short circuit, the trigger is immediately overturned through the strong positive feedback action of the feedback unit in the trigger, the power tube is immediately cut off and is self-locked in a cut-off state, and the overcurrent protection is effectively carried out on the power tube.

Several voltage regulators using the flip-flop described above will be described below with reference to the drawings.

In a fourth aspect, an embodiment of the present invention provides a voltage regulator, as shown in fig. 4, where the voltage regulator includes a first flip-flop, and further includes: a flywheel unit 41, a voltage stabilizing unit 42, a sampling unit 43, an error comparing and amplifying unit 44, an oscillation unit 45, a shaping unit 46, and a reference threshold setting unit 47;

the follow current unit 41 is connected to the positive electrode of the power supply (i.e. the output end of the voltage of the generator to be regulated) and the control end of the trigger (end F in fig. 4), and is configured to form a follow current loop with a load connected between the end F and the positive electrode of the power supply, so as to absorb induced electromotive force generated by the load; the voltage stabilizing unit 42 is connected with the power supply anode, the ground, the reference threshold setting unit 47, the oscillating unit 45 and the comparing unit 1, and is used for providing stable voltage for the reference threshold setting unit 47 and the comparing unit 1; the sampling unit 43 is connected to the positive electrode of the power supply, the ground and the non-inverting input terminal of the error comparing and amplifying unit 44, and is configured to provide a sampling voltage to the non-inverting input terminal of the comparing and amplifying unit; the reference threshold setting unit 47 is connected to the inverting input terminal of the error comparing and amplifying unit 44, the ground, and the non-inverting input terminal of the comparing unit 1, and is configured to provide a first threshold voltage for the inverting input terminal of the error comparing and amplifying unit 44 and a second threshold voltage for the non-inverting input terminal of the comparing unit 1; the output end of the error comparing and amplifying unit 44 is connected to the comparing unit 1, and is configured to provide a first voltage to the inverting input end of the comparing unit 1 when the voltage at the non-inverting input end is greater than the voltage at the inverting input end, where the first voltage is greater than a second threshold voltage; the oscillating unit 45 is connected with the ground and the shaping unit 46, the shaping unit 46 is connected with the non-inverting input end of the comparing unit 1, the oscillating unit 45 inputs narrow pulses to the non-inverting input end of the comparing unit 1 under the action of the shaping unit 46, the peak voltage of the narrow pulses is larger than the amplitude limiting voltage value of the amplitude limiting diode D5, the trigger is enabled to reliably turn to the setting state of the conduction of the power tube under the action of the narrow pulses and to be self-locked, and the excitation current of the generator is switched on.

Each unit in the voltage regulator may have various implementations, which are illustrated below: as shown in fig. 4, a first type of flip-flop is applied to the voltage regulator. In this flip-flop, the comparison unit 1 is a comparator a 1; the switch unit 2 is a power tube Q2, the drain electrode of which is connected with the F end, and the source electrode is grounded; the feedback unit 3 comprises resistors R22 and R7 and a clipping diode D5, one end of the resistor R7 is connected to the drain of the power tube Q2, the other end of the resistor R7 is connected to the cathode of the clipping diode D5 and one end of the resistor R22, the anode of the clipping diode D5 is grounded, and the other end of the resistor R22 is connected to the inverting input end of the comparator a1 through a P3 node.

In the voltage regulator provided by the embodiment of the present invention, the peripheral circuit of the flip-flop is specifically as follows: the freewheeling unit 41 is connected between the positive electrode of the power supply (the voltage output end of the generator to be tested, i.e., the end D +/B + shown in fig. 4) and the end F; the voltage regulation unit 42 comprises a resistor R6 and a voltage regulation diode D3, wherein the resistor R6 is connected between the D +/B + end and the VC node, and the voltage regulation diode D3 is connected between the Vc node and the ground; the sampling unit 43 comprises a resistor R1 and a resistor R2 connected in series; the reference threshold setting unit 47 includes resistors R8, R9, and R10, a voltage of a P4 node between R8 and R9 is used to provide a first threshold voltage, and is output to an inverting input terminal of the comparator a2, and a voltage of a P1 node between R9 and R10 is a second threshold voltage, and is output to a non-inverting input terminal of the comparator a 1; the error comparing and amplifying unit 44 comprises a comparator A2 and a diode D6, wherein the inverting input end of the comparator A2 is connected with the P1 node, the signal output end of the comparator A2 is connected with the anode of a diode D6, and the cathode of a diode D6 is connected with the inverting input end of a comparator A1; in addition, the oscillating unit 45 is connected to the non-inverting input terminal of a1 through a diode D4 in the shaping unit 46, and the oscillating unit 45 is also connected to the regulated power Vc terminal and ground.

The operation of this voltage regulator is described in detail as follows:

the reference threshold setting unit 47 provides a constant first threshold voltage to the inverting input of the comparator a2 under the action of the Vc node. Wherein the magnitude of the first threshold voltage can be set according to practical situations by adjusting the magnitudes of R8, R9 and R10. The sampling unit collects the voltage of the power supply anode of the generator to be regulated (namely the voltage of the D +/B + end), and after the voltage is divided by R1 and R2, the voltage of the P6 node is input to the non-inverting input end of the comparator A2 so as to be compared with the first threshold voltage. It is easy to understand that, by reasonably setting the magnitudes of R1 and R2 and the magnitude of the first threshold voltage in the sampling unit, the magnitude relationship between the voltage of the P6 node and the first threshold voltage can be used to indirectly reflect the magnitude relationship between the voltage of the positive electrode of the power supply and the preset threshold voltage of the generator. Upon comparison by comparator a2, the following two results may occur:

(1) when the voltage of the P6 node is less than the first threshold voltage, that is, the voltage of the positive pole of the power supply is lower than the preset threshold voltage of the generator:

the output of the comparator A2 is low, and the diode D6 is turned off, so the inverting input of the comparator A1 is only affected by the voltage at the P3 node. The voltage at node P3 is controlled by the positive feedback signal at terminal F and the limiting diode D5 in the feedback unit 3. The limiter voltage value of the limiter diode D5 is set to be lower than the peak voltage of the narrow pulse signal output by the shaping unit 46, but higher than the saturation voltage drop of the power transistor Q2 when it is normally turned on, i.e., the voltage value of the power transistor drain. The reference threshold setting unit 47 provides a constant second threshold voltage for the non-inverting input terminal of the comparator a1 through the P1 node under the action of the Vc node, and according to the power requirement of the generator and the parameters of the power tube, the second threshold voltage can be set by reasonably adjusting the magnitudes of R8, R9 and R10, that is, a certain margin range should be reserved on the basis of the conduction saturation voltage drop of the power tube for the magnitude of the second threshold voltage, so that a control point for overcurrent protection of the power tube is set, and high-precision overcurrent protection is realized. While the non-inverting input of comparator a1 is also controlled by oscillating unit 45 and shaping unit 46. The narrow pulse signal output from the oscillating unit 45 passes through the diode D4 of the shaping unit 46, and then outputs a constant frequency trigger narrow pulse or an edge pulse, and the pulse signal is in a high impedance state during a non-narrow pulse period or a non-edge period. The pulse signal is input to the non-inverting input of comparator A1 via node P1.

When the pulse signal is at a high level, the P1 node is influenced by the pulse signal to input the peak voltage of the pulse signal to the non-inverting input terminal of the comparator a 1. Since the amplitude-limiting voltage value of the diode D5 is set to be lower than the peak voltage of the narrow pulse signal output by the shaping unit 46, the potential of the non-inverting input terminal of the comparator a1 is higher than that of the inverting input terminal thereof, and the comparator a1 outputs a high level, so that the power transistor Q2 is turned on. The voltage at the end F is reduced to the very low saturation voltage drop of the power tube Q2. At this time, the generator is connected to the exciting coil between the terminal F and the positive terminal D +/B + of the power supply to generate exciting current, and the generator is excited.

After the pulse signal is at a low level, i.e., after the narrow pulse peak, the diode D4 in the shaping unit 46 is turned off, and at this time, the node P1 inputs the second threshold voltage to the non-inverting input terminal of the comparator a 1. The voltage of the terminal F is input to the inverting input terminal of the comparator a1 through the p3 node via the resistors R7 and R22 of the feedback unit, and since the clipping voltage value of the diode D5 is set to be higher than the voltage of the terminal F when the power transistor Q2 is normally turned on, the clipping diode D5 is turned off at this time. Since the second threshold voltage is set higher than the voltage fed back from the terminal F to the inverting input terminal a1, the comparator a1 outputs a high voltage, and the power transistor Q2 is still turned on. As long as the power tube Q2 is in saturated conduction, the voltage of the inverting input end of the comparator A1 can be kept lower than the voltage of the non-inverting input end to output high level, so that the power tube Q2 is kept in a conduction setting state, and a generator connected between the F end and the D +/B + end is kept in a normal power generation and excitation setting state.

Therefore, when the voltage of the positive electrode of the power supply is lower than the preset threshold voltage of the generator, the power tubes can be kept conducted, and the generator can be excited normally.

(2) When the voltage of the node P6 is greater than or equal to the first threshold voltage, that is, the voltage of the positive pole of the power supply is greater than or equal to the preset threshold voltage of the generator, and is in an overvoltage state, when the triggering narrow pulse does not arrive:

the comparator A2 outputs high potential, and the diode D6 is conducted; d4 is turned off because the trigger narrow pulse does not arrive. At this time, the inverting input of a1 is controlled primarily by the voltage output from diode D6. The voltage output by the diode D6, i.e., the voltage at the node P2, is higher than the second reference threshold voltage, so the comparator a1 outputs a low voltage level of 0, turning off the power transistor Q2, and the flip-flop immediately flips. The voltage at the end F of the drain electrode is pulled up to the same magnitude as that of D +/B + by the excitation coil of the generator, the excitation current is cut off, and the generator stops generating electricity.

With the gradual consumption of the load to the power supply, when the output voltage of the generator is reduced to be lower than the preset threshold voltage, the voltage of the node P6 is smaller than the first threshold voltage, the comparator a2 outputs a low potential, the diode D6 is cut off, meanwhile, the voltage of the terminal F is pulled high and then is limited at the limiting diode D5 through the resistor R7 of the feedback unit 3, at this time, the inverting input terminal of the comparator a1 is the limited voltage of the diode D5, which is higher than the second threshold voltage, namely the voltage of the non-inverting input terminal of the a1, so that the a1 keeps outputting the low level, and the power tube Q2 keeps the cut-off state and locks, thereby keeping the excitation current in the cut-off.

When the next fixed-frequency trigger pulse arrives, the trigger is turned over, the power tube is conducted again, and excitation of a new period is started, namely, the generator starts to generate power continuously.

It should be noted that during the generator overvoltage condition, the non-inverting input of the comparator a1 is also affected by the fixed-frequency trigger pulse signal output by the oscillating unit 45, specifically, there are the following two cases:

A. when the peak value of the constant-frequency trigger pulse signal output by the oscillation unit 45 is designed to be higher than the node voltage of the output end P2 of the error comparison amplification unit, the comparator A1 can output a high-level narrow pulse at the moment of continuous overvoltage when the constant-frequency trigger narrow pulse or edge pulse arrives, so that the power tube is momentarily conducted, and the conduction narrow pulse synchronous with the constant-frequency trigger signal, namely 'residual current', appears in the excitation loop, thereby being beneficial to the frequency consistency of observation;

B. when the pulse peak value output by the oscillating unit 45 is designed to be lower than the voltage of the P2 node, the narrow pulse triggered at the fixed frequency or the edge pulse does not enable the comparator A1 to output the narrow pulse with high level when the voltage is over-voltage, the power tube is always cut off, and no residual current appears in an excitation loop.

The design of the oscillating unit 45 essentially serves two purposes: firstly, triggering through a fixed-frequency pulse to enable a trigger to be set and start excitation in a fixed-frequency mode; and secondly, narrow pulses are generated to ensure that the duration of the overcurrent peak of the power tube is short enough during overcurrent, and the narrow pulses of the power tube are overcurrent protection reset pulses and load short circuit detection pulses. When the power tube is in overcurrent during excitation, the voltage drop Uds between the drain electrode and the source electrode is increased, when the set second threshold voltage is exceeded, the higher drain electrode potential of the power tube is input to the inverting input end of the comparator A1 through the resistor R7 and the resistor R22 of the feedback unit, when no fixed frequency trigger signal arrives, the inverting input end of the comparator A1 is higher than the potential of the non-inverting input end, the trigger is turned over, the power tube is immediately cut off and locked to be protected, and when the next fixed frequency trigger signal arrives, the power tube is turned on again; when an excitation winding of the generator is continuously short-circuited, only when a constant-frequency trigger signal, namely a narrow pulse, arrives, the power tube can be briefly conducted in a narrow-pulse high-level period, an excitation loop generates an extremely narrow pulse conducted by the power tube, the pulse is a short-circuit monitoring pulse, and after overcurrent and short-circuit faults are relieved, the normal operation is automatically recovered.

When the output voltage of the generator is lower than a preset generator voltage threshold value, the pulse output by the oscillation unit 45 is input to the non-inverting input end of the comparator A1 after being shaped, and the trigger is enabled to be in a setting state of conducting excitation of the power tube in a self-locking mode through the positive feedback effect of the feedback unit; when the output voltage of the generator is higher than the preset voltage threshold value of the generator, the comparator A2 outputs a high-level overvoltage signal, namely a reset signal to the inverting input end of the comparator A1, through strong positive feedback action, the trigger immediately turns over and self-locks in a reset state of the cut-off of the power tube, meanwhile, the feedback unit also serves as an overcurrent detection circuit of the power tube, and when the overcurrent of the power tube is caused by load short circuit and the like, the trigger is also reset, so that the power tube is protected in time.

In summary, the voltage regulator provided by the embodiment of the present invention is suitable for triggering excitation at a fixed frequency, is suitable for cutting off excitation without delay, and has a function of overcurrent protection, and is particularly suitable for a generator voltage regulator with high reliability. The excitation frequency is determined by the oscillation circuit, the voltage division node of the sampling circuit is not provided with a filter capacitor, and the sampling signal cannot generate delay, so that the excitation is cut off without delay, the overcurrent impact on a rectifier bridge, a power tube and the like caused by delay is effectively prevented, and the regulation precision and the safety and reliability of the regulator are improved.

In a fifth aspect, an embodiment of the present invention provides another voltage regulator, as shown in fig. 5, where the voltage regulator includes the second flip-flop, and further includes: a freewheel unit 51, a first voltage stabilization unit 52, a second voltage stabilization unit 53, a sampling unit 54, an oscillation unit 55, and a shaping unit 56;

the freewheeling unit 51 is connected to the positive electrode of the power supply (i.e., the output end of the generator voltage to be regulated, i.e., the D +/B + end shown in fig. 5) and the control end of the trigger (the F end in fig. 4), and is configured to form a freewheeling loop with the load connected between the F end and the positive electrode of the power supply, so as to absorb the induced electromotive force generated by the load; the first voltage stabilizing unit 52 is connected to the positive electrode of the power supply, the ground, the switch control unit and the oscillating unit 55, and is used for providing stable voltage for the switch control unit and the oscillating unit 55; the sampling unit 54 is connected with the positive electrode of the power supply, the ground and the second voltage stabilizing unit 53, the second voltage stabilizing unit 53 is connected with the input end of the switch control unit, the sampling unit 54 provides an overvoltage signal for the input end of the switch control unit under the voltage stabilizing effect of the second voltage stabilizing unit 53, so that the trigger is reset to be in a cut-off state of the switch unit and is self-locked under the triggering of the overvoltage signal, and the excitation current of the generator is cut off; the oscillating unit 55 is connected with the ground and the shaping unit 56, the shaping unit 56 is connected with the input end of the switch control unit, the oscillating unit 55 inputs narrow pulses to the switch control unit under the action of the shaping unit 56, the trigger is set to be in a switch unit conducting state under the trigger of the narrow pulses and is self-locked, and the generator exciting current is switched on.

Each unit in the voltage regulator may have various implementations, which are illustrated below: as shown in fig. 5, the second type of flip-flop is applied to the voltage regulator. In this flip-flop, the switch control unit 4 is constituted by a transistor Q4 and a resistor R13, an emitter of the transistor Q4 is grounded, and a collector is connected to the resistor R13. The end of resistor R13 not connected to transistor Q4 is connected to the Vc node in fig. 5. The switch unit 2 is a power transistor Q2, the gate of which is connected to the node between the resistor R13 and the transistor Q4, the drain of which is connected to the control terminal, i.e., the F terminal, and the source of which is grounded. The feedback unit 3 is formed by connecting anti-parallel switching diodes D7 and D8 in series with a resistor R11. The ends of the anti-parallel switch diodes D7 and D8, which are not connected with the resistor R11, are connected with the end F, and the end of the resistor R11, which is not connected with the resistors D7 and D8, is connected with the base stage of the triode Q4. The emitter junction conduction threshold of the transistor Q4 is also used for comparison with the saturation voltage drop of the power transistor Q2 as the starting control point of the overcurrent protection of the power transistor Q2, and the diode D8 is added to the feedback unit 3 to adjust the starting control point of the overcurrent protection.

In the voltage regulator provided by the embodiment of the present invention, the peripheral circuit of the flip-flop is specifically as follows: the freewheeling unit 51 comprises a diode D2 connected with the positive pole of the coil of the generator to be regulated and the drain of the power tube Q2; the first voltage regulation unit 52 includes a resistor R6 and a voltage regulation diode D3, one end of the resistor R6 is connected to the D +/B + terminal, the other end is connected to the cathode of the voltage regulation diode D3, and the anode of the voltage regulation diode D3 is grounded. The second voltage regulation unit 53 is connected between the node P4 and the node P2, and includes two diodes D10 and a zener diode D11 connected in reverse. The sampling unit 54 is connected between the D +/B + terminal and ground, and includes a resistor R1 and a resistor R2 connected in series. Oscillation section 55 is connected to Vc node and shaping section 56. The shaping unit 56 is composed of an input capacitor C1, a diode D9, a resistor R12, and a switching tube Q3. One end of the input capacitor C1 is connected with the oscillation unit 55, and the other end is connected with the base electrode of the switch tube Q3; the collector of the switching tube Q3 is connected with the P1 node, and the emitter is connected with the ground; the anode of the diode D9 is grounded, and the cathode is connected with the node P5; resistor R12 is connected between the P5 node and ground.

The operation of this voltage regulator is described in detail as follows:

the sampling unit 54 collects the voltage of the positive pole of the power supply of the generator to be regulated (i.e. the voltage at the D +/B + end), and after dividing the voltage by R1 and R2, the voltage at the p4 node is input into the second voltage stabilizing unit 53 to be compared with the sum of the regulated voltage values of the diodes D11 and D10 in the second voltage stabilizing unit 53 and the conduction threshold of the emitter junction of the transistor Q4. It is easy to understand that by reasonably setting the regulated voltage values of R1 and R2, D11 and D10 and the conduction threshold value of the Q4 emitter in the sampling unit, the magnitude relation between the voltage of the positive electrode of the power supply and the preset threshold voltage of the generator can be indirectly reflected by the magnitude relation between the voltage of the p4 node and the sum of the voltages of the latter three, that is, the ratio between the real-time value of the output voltage of the generator and the voltage value of the p4 signal of the sampling node, and the ratio between the set value of the output voltage of the generator and the sum of the voltages of the three are the same value. The following two results may occur:

(1) if the voltage of the p4 node is less than the sum of the regulated voltage values of D11 and D10 and the conduction threshold of the emitter of the triode Q4, that is, if the voltage of the corresponding power supply anode is lower than the preset generator threshold voltage:

the diodes D10, D11 turn off and the base voltage of transistor Q4 is not affected by the p2 node. The pulse signal output by the oscillating unit 55 is subjected to phase inversion amplification after passing through the shaping unit 56, and the capacitor C1 is connected with the emitter equivalent input resistor of the switching tube Q3 in a differential unit form, and the capacitor C1 has a small capacity, so that the switching tube Q3 is only turned on at the steep rising edge moment of the pulse transmitted by the capacitor C1. The collector of the transistor Q3 generates a very narrow low-level narrow pulse, and during the non-narrow pulse period, i.e. after the narrow pulse, the collector output of the transistor Q3 is in an open-circuit state, i.e. a high-impedance state. When the steep front edge of the pulse transmitted by the capacitor C1 arrives, the rising edge reaches the switching tube Q3 through the capacitor C1 and is amplified, and the base voltage of the triode Q4 is pulled down by the collector of the switching tube Q3 through the p1 node. At this time, a strong positive feedback process is performed in the flip-flop, so that the transistor Q4 is turned off, and the power transistor Q2 is in a saturation conducting state (the power transistor Q2 is exemplified as an NMOS type field effect transistor). The feedback process specifically comprises the following steps: the voltage of the base electrode of the triode Q4 is pulled low → the collector voltage of the triode Q4 is increased → the grid potential of the power tube Q2 is increased → the drain electrode potential of the power tube Q2 is reduced → the base electrode potential of the triode Q4 is reduced → the voltage of the F end is reduced to the saturation voltage drop of the drain electrode until the power tube Q2 is conducted in a saturation mode, and after the steep front edge of the pulse transmitted by the capacitor C1 passes, the low saturation voltage drop of the F end is not enough to conduct the triode Q4 through the diode D8; meanwhile, a power supply for supplying power after voltage stabilization, namely, the voltage of the Vc node (based on the field effect transistor adopted in the embodiment, the voltage Vc value of the stabilized voltage supply should be designed within a safety range allowed by a grid electrode of the field effect transistor, and meanwhile, the stabilized voltage Vc value is fully and reliably turned on, and can be generally set to 8-12V, but not limited to the range), the power tube Q2 is in saturation conduction through the resistor R13, excitation current occurs, and meanwhile, the saturation voltage drop of the power tube Q2 is low and is not enough to turn on the triode Q4, at this time, because the output voltage of the generator is lower than a preset voltage value, the diodes D10 and D11 are both cut off, so that the triode Q4 is reliably cut off, and the trigger.

Because a trigger self-locking mode is adopted, the trigger is locked in a triode Q4 locking cut-off state at the moment, the control electrode of the power tube Q2, namely the voltage of the grid comes from a stabilized power supply through a resistor R13, the voltage regulator is different from the existing voltage regulator in that clutter components in a sampling unit voltage division node signal are introduced into the control electrode of the power tube, the clutter interference waveform on the sampling node cannot occur in the conducting period of the power tube Q2, and the power tube cannot be detained in an amplifier, so that the temperature rise is reduced, and the fault rate is reduced; and therefore no capacitor filtering is required at the sampling node.

(2) If the voltage of the p4 node is greater than or equal to the sum of the regulated voltage values of D11 and D10 and the conduction threshold of the Q4 emitter, that is, the voltage of the positive pole of the power supply is greater than or equal to the preset threshold voltage of the generator:

an overvoltage signal is generated at node p 2. The overvoltage signal changes in real time along with the output voltage of the generator and belongs to an analog signal, namely a diode D10 and a voltage stabilizing diode D11 are used for detecting the analog signal as a reset signal, and the PN junction conduction threshold of the base electrode and the emitting electrode of the triode Q4 is the starting control point of the reset signal. When the detected overvoltage signal reaches the conduction threshold of the PN junction, the overvoltage signal is amplified as a reset signal by the transistor Q4, i.e., the overvoltage signal saturates and conducts the transistor Q4 as a reset signal by the p 2. After the transistor Q4 is turned on in saturation, the gate potential of the power transistor Q2 is pulled low, the power transistor Q2 is turned off, and the excitation current is cut off. After the exciting current is cut off, the drain potential of the power tube Q2, that is, the voltage at the F end, rises under the action of the D +/B + end, the voltage value at the F end is injected into the base of the triode Q4 through the diode D8 and the resistor R11, the base current of the triode Q4 is increased, and a strong positive feedback process is formed, specifically: the base voltage of the triode Q4 is pulled high → the collector voltage of the triode Q4 is reduced → the gate potential of the power tube Q2 is reduced → the power tube Q2 is cut off, so that the drain voltage, namely the voltage of the terminal F is increased → the voltage of the terminal F is transmitted to the base of the triode Q4 through the diode D8 and the resistor R11, so that the base voltage of the triode is increased, the trigger is turned over rapidly, and the power tube Q2 is cut off, so that the exciting current on the exciting coil is cut off. After the flip-flop is turned over, the current flowing through the resistor R11 is enough to maintain the transistor Q4 in a saturated state, even if the sampling unit 54 does not provide the base current for the transistor Q4 any more, as long as the leading edge of the constant-frequency trigger pulse output by the oscillating unit 55 does not arrive, the switch control unit is always self-locked in a state of cutting off the excitation, i.e., in a reset state of cutting off the power tube Q2, so that the excitation current on the excitation coil is kept in a cutting-off state. Because of adopting the self-locking mode of the trigger, the trigger is locked in the conduction state of the triode Q4 at this moment and locks various interference clutter in the sampling signal, the control electrode of the power tube Q2 is grounded by the triode Q4, different from the existing voltage regulator, the clutter component in the voltage division node signal of the sampling unit is introduced into the control electrode of the power tube, the clutter interference waveform on the sampling node can not appear in the conduction period of the power tube Q2, the power tube can not be detained in the amplifier, thereby reducing the temperature rise and the failure rate; and therefore no capacitor filtering is required at the sampling node;

therefore, the delay of the sampling signal caused by the RC resistance-capacitance circuit is avoided, the overvoltage excitation is fundamentally avoided, the delay of excitation cut-off is avoided, and the safety and reliability of the regulator, the generator and related electrical equipment are improved; meanwhile, the amplitude of the real-time sampling signal is not attenuated by the capacitor, so that the sensitivity and the responsiveness of voltage regulation are improved, and the voltage regulation is more accurate.

When the leading edge of the next trigger signal does not arrive in one period of the constant-frequency trigger signal output by the oscillating unit 55, even if the output voltage of the generator is monitored to be lower than the preset threshold voltage of the generator, namely the set value due to the consumption of the load current, at the moment, the diodes D10 and D11 are cut off, the triode Q4 is still in saturated conduction, and the trigger keeps the excitation cut-off state. At this time, the transistor Q4 cannot be turned off even if the sampling signal is low, the voltage fluctuation on the sampling signal is not transmitted to the gate of the power transistor Q2, and the power transistor Q2 can be stabilized in the off state.

The two conditions (1) and (2) are cyclically generated along with the change of the output voltage of the generator in actual conditions, namely the working conditions of normal regulation of the generator are met.

In addition, under the generator lasts the under-voltage and lasts the extreme operating mode of under-voltage, specifically: if the output voltage of the generator is monitored to be continuously undervoltage, the trigger is always in an excitation state, and the excitation duty ratio is 100%; when the output voltage of the generator rises to be greater than or equal to the preset generator threshold voltage, the triode Q4 is conducted again, the Q2 is cut off, and the exciting current is cut off; if the generator is continuously in overvoltage, the triode Q4 is conducted, the power tube Q2 is cut off, and the exciting current is cut off; when the leading edge of the trigger pulse comes, the switching tube Q3 makes the triode Q4 cut off in the conducting narrow pulse time, so that the power tube Q2 is conducted, and the exciting current appears, but due to continuous overvoltage, after the constant-frequency trigger narrow pulse or the leading edge passes, the switching tube Q3 is cut off, the triode Q4 is conducted, the power tube Q2 is cut off, and the exciting current is cut off again, for example, the secondary cycle is repeated. Pulse currents, which trigger narrow pulses or their edge widths, occur in the excitation circuit and are referred to as "residual currents". The duty cycle of this residual current is generally allowed to not exceed 5% to 7% (for illustration only, not as a numerical limitation) under the electrical parameters of the automotive generator. Considering the excitation short-circuit protection factor, the duty ratio of the residual current should be properly reduced for the safety of the power tube. In the present embodiment, the width of the edge may be less than 1%, for example, less than 0.3%, which is not particularly limited in the present invention. The edge-on excitation pulses occurring during this period are referred to as monitoring pulses for monitoring short circuits.

When overcurrent occurs in the power tube (for example, short circuit of an excitation winding, electric leakage, short circuit of a carbon brush, electric leakage between slip rings due to graphite powder and the like occurs), the voltage drop (Uds) on the conduction internal resistance of the power tube Q2 is increased, when the Uds voltage is increased to be more than or equal to the sum of conduction thresholds of an emitter junction of the diode D8 and the triode Q4, the excessively high Uds voltage is injected into the base electrode of the triode Q4 through the D8 and the R11 to enable the triode Q4 to be conducted, and the trigger is turned over rapidly after a strong positive feedback process, so that the cut-off of the power tube Q2 is protected. The current flowing through the resistor R11 is sufficient to maintain the power transistor Q2 in a saturated state, even if the sampling circuit no longer provides base current for the transistor Q4 or the short-circuit fault is relieved, the circuit is maintained in a state of cutting off the excitation as long as the leading edge of the constant-frequency trigger pulse output by the oscillating unit does not arrive, and the power transistor Q3 is locked in a cut-off state as a result of the over-current or short-circuit protection state. After overcurrent or short circuit is removed, when the generator is in an undervoltage state, the trigger is turned to an excitation state under the trigger of the next trigger pulse, namely the power tube Q2 is conducted, and the voltage regulator automatically restores to normal excitation.

It should be noted that, in the voltage regulator provided in this embodiment, the diode D8 may be used to adjust a start-control point of overcurrent protection, and also to prevent a protection circuit from being triggered by an increase in conduction internal resistance and an increase in saturation voltage drop caused by a temperature drift of the switching tube Q3, and D8 and D7 may be omitted when the temperature-rising environment allows; d10 is used to adjust the temperature characteristics of the regulated voltage, and in some particular cases D10 may be omitted.

When the output voltage of the generator is greater than or equal to a preset generator voltage threshold value or the power tube is in overcurrent, for example, when the excitation winding is in short circuit, the power tube Q2 is cut off, namely reset and self-locked, so that the excitation current is cut off, and the power tube Q2 is protected; when the output voltage of the generator is smaller than the preset voltage threshold, if the power tube Q2 is in a cut-off self-locking state at the moment, the power tube Q2 can be turned on, i.e., set and self-locked, through a constant-frequency trigger pulse signal input to the switch control unit 4, so that excitation is recovered. Meanwhile, in the process, the feedback unit 3 is also used as an overcurrent detection circuit of the power tube Q2, the conduction internal resistance of the power tube Q2 is also used as an overcurrent sampling resistor, and the switch unit 4 is also used as an overcurrent protection execution circuit, so that the trigger circuit and the overcurrent protection circuit become a multifunctional composite circuit with the same structure, and multiple functions of the trigger are realized by an extremely simple circuit structure. The voltage regulator is particularly suitable for a high-reliability fixed-frequency excitation automobile generator voltage regulator.

In addition, the voltage regulator provided by the embodiment of the invention adopts a circuit structure of discrete components, and can meet the requirements of constant-frequency excitation, non-delay cut-off excitation, overcurrent protection and higher working temperature under the conditions of simple structure and low cost by utilizing the working temperature advantage of the discrete components. Meanwhile, in order to further reduce the occupied space of the circuit, the voltage regulator provided by the embodiment of the invention can adopt a structure that a double transistor or a transistor array or integrated package is used as a chip circuit, so that the temperature resistance of the regulator product can be ensured, and more functions such as pre-excitation current control of shutdown duty ratio, indicator lamp control, remote sampling, regulation point external control, soft loading, data control and the like can be added on the limited circuit area, so that the practicability of the voltage regulator is increased, and the application range of the trigger is expanded.

In a sixth aspect, an embodiment of the present invention further provides a voltage regulator, as shown in fig. 6, which similarly includes the second flip-flop, and further includes: a freewheeling block 61, a third voltage regulation block 62, a fourth voltage regulation block 63, a sampling block 64, an oscillating block 65 and a shaping block 66.

The follow current unit 61 is connected with the negative electrode of the power supply and a trigger control end (end F), namely an excitation control end, and is used for forming a follow current loop with a load connected between the end F and the negative electrode of the power supply and absorbing induced electromotive force generated by the load; the third voltage stabilizing unit 62 is connected to the positive electrode of the power supply, the ground, the oscillating unit 65 and the pump power supply input end of the switch control unit 4, and is configured to provide different stabilizing voltages for the oscillating unit 65 and the switch control unit 4; the sampling unit 64 is connected with the positive electrode of the power supply, the ground and the fourth voltage stabilizing unit 63, and is used for providing an overvoltage signal for the input end of the switch control unit 4 under the voltage stabilizing effect of the fourth voltage stabilizing unit 63, so that the trigger is reset and self-locked under the triggering of the overvoltage signal and is used for cutting off the excitation current of the generator; the oscillating unit 65 is connected with the ground and the shaping unit 66, the shaping unit 66 is connected with the input end of the switch control unit 4, the oscillating unit 65 inputs narrow pulses to the switch control unit 4 under the action of the shaping unit 66, and the trigger is set to be in a conducting state of the switch unit 2 under the triggering of the narrow pulses and is self-locked to be used for connecting the excitation current of the generator.

Each unit in the voltage regulator may have various implementations, which are illustrated below: as shown in fig. 6, the second flip-flop is applied to the voltage regulator. In the flip-flop, the switch control unit 4 includes a transistor Q4 and a resistor R13, an emitter of the transistor Q4 is grounded, i.e., an E terminal, and a collector is connected to the resistor R13. The end of the resistor R13 not connected to the transistor Q4 is connected to the pump power supply Vp node in fig. 5, and a resistor R16 is connected between the base of the transistor Q4 and ground. The switching unit is a power tube Q2, a gate of the switching unit is connected to a collector of a transistor Q4, i.e., a p4 node, a drain of the switching unit is connected to a power supply end, i.e., a B + end, and a source of the switching unit is connected to an F end, wherein the F end is a control end of an excitation winding (i.e., an excitation coil). In addition, a protection diode D15 is connected between the grid and the source. The feedback unit comprises a resistor R14, a diode D12, a diode D13, a triode Q5 and a resistor R15. One end of the resistor R14 is connected with the source electrode of the power tube Q2, the other end of the resistor R14 is connected with the base electrode of the triode Q5 through the anti-parallel diodes D12 and D13, the emitter electrode of the triode Q5 is connected with the B + end, the collector electrode of the triode Q5 is connected with the resistor R15, and the other end of the resistor R15 is connected with the base electrode of the triode Q4. The PN junction conduction threshold of the base electrode and the emitter electrode of the triode Q5 is also used for being compared with the saturation voltage drop of the power tube Q2 to serve as a starting control point of overcurrent protection of the power tube. In addition, a diode D13 is added in the feedback unit to adjust the starting point of the overcurrent protection of the power tube. The peripheral circuit of the flip-flop is specifically as follows: the freewheeling unit is diode D2. The third voltage stabilizing unit further comprises a pump power supply circuit for generating a pump power supply voltage, wherein the output voltage Vp of the output end of the pump power supply circuit is at least higher than the voltage B + of the power supply end of the voltage regulator power supply and has a gate-source voltage value suitable for reliable turn-on of the field effect transistor, for example, for a 14V system circuit, the output voltage of the pump power supply can be set to be 18-22V. The shaping unit comprises a capacitor C1, a resistor R12 and a switching tube Q3. One end of the capacitor C1 is connected with the output end of the oscillation unit, and the other end is connected with the base electrode of the switch tube Q3. The collector of the switching transistor Q3 is the output of the shaping unit and is connected to the base of the transistor Q4. The resistor R12 is connected in parallel between the base and the emitter of the switch tube Q3, and the emitters of the triodes Q3 and Q4 are both grounded, namely the E end.

The operation flow of this voltage regulator is specifically described as follows:

the sampling unit collects the power supply voltage (namely the voltage at the B + end) of the generator to be regulated, and after the power supply voltage is divided by R1 and R2, the voltage at the p5 node is input into the fourth voltage stabilizing unit so as to be compared with the sum of the regulated voltage value of the diode D14 in the fourth voltage stabilizing unit and the conduction threshold value of the emitting stage of the triode Q4. It is easy to understand that, by reasonably setting the regulated voltage values of R1 and R2 and D14 and the magnitude of the turn-on threshold of the Q4 emitter in the sampling unit, the magnitude relation between the voltage of the negative pole of the power supply and the preset threshold voltage of the generator can be indirectly reflected by the magnitude relation between the voltage of the p5 node and the sum of the latter two voltages. The following two results may occur:

(1) if the voltage at the p5 node is less than the sum of the regulated voltage value of D14 and the conduction threshold value of the Q4 emitter, that is, if the power supply voltage is lower than the preset generator threshold voltage:

the zener diode D14 is turned off, the constant frequency trigger signal output by the oscillation unit is changed into a narrow pulse signal or an edge pulse signal after being processed by the shaping unit, and the signal output is in a high impedance state during a non-narrow pulse period or a non-edge pulse period.

The negative narrow pulse signal or the edge pulse signal output by the collector of the switching tube Q3 is input to the base stage of the transistor Q4 through the p1 node, so that the transistor Q4 is cut off. The voltage output by the pump power supply unit in the third voltage stabilizing unit is input to the gate of the power tube Q2 through the resistor R13 and the p4 node, so that the power tube Q2 is turned on. Because the saturation on-resistance Rds of the power tube Q2 is extremely small, the voltage of the F terminal connected to the source of the power tube Q2 is close to the voltage of the B + terminal, and the voltage of the F terminal is not enough to turn on the emitter junction of the triode Q5 in the feedback unit through D13 and R14, so that the triode Q5 is in an off state, even if the negative narrow pulse at the collector output terminal of the triode Q3 has passed, i.e., the triode Q3 is already turned off, so far no current flows through the base of the triode Q4 in the switch control unit, the triode Q4 is kept off, the power tube Q2 is kept in an on state, and the source, i.e., the F terminal, outputs a high potential, so that state self-locking is realized, i.e., a trigger composed of the switch control unit, the.

(2) If the voltage of the p5 node is greater than or equal to the sum of the D14 regulated voltage value and the Q4 emitter junction conduction threshold, namely, the power supply voltage is greater than or equal to the preset generator threshold voltage:

the sampling unit output voltage is higher than the sum of the regulated voltage of the zener diode D14 and the emitter junction conduction threshold of the transistor Q4, which will generate an overvoltage signal at the anode of the diode D14. The overvoltage signal changes in real time along with the output voltage of the generator and belongs to an analog signal, namely a voltage stabilizing diode D14 is used for detecting the analog signal as a reset signal, and the emitter junction conduction threshold of the triode Q4 is used as a starting control point of the reset signal. When the detected over-voltage signal reaches the conduction threshold of the emitter junction of the transistor Q4, the over-voltage signal will saturate the transistor Q4 via the p2 node as a reset signal, thereby causing a strong positive feedback process, specifically: the base potential of the transistor Q4 is pulled high → the collector potential of the transistor Q4 is lowered → the gate potential of the power tube Q2 is pulled low → the source potential of the power tube Q2, that is, the potential of the terminal F is lowered → the base potential of the transistor Q5 is lowered under the action of the resistor R14 and the diode D13 → the collector potential of the transistor Q5 is turned on and raised → the base potential of the transistor Q4 is raised under the action of the resistor R15, so that the flip-flop is immediately turned over, the power tube Q2 is turned off, and the voltage of the terminal F is lowered to almost the same voltage as that of the terminal E, so that the exciting current between the terminal F and the terminal E is cut off. Even if the generator output voltage is restored to be lower than the preset generator threshold voltage along with the consumption of the load at this time, the base current of the transistor Q4 is not affected by the sampling signal any more, which is due to the self-locking of the trigger, specifically: because the triode Q5 is conducted, the collector electrode of the triode Q5 passes through the resistor R15 and then the p3 node to connect the base current for the triode Q4, the triode Q4 is in saturated conduction, the power tube Q2 keeps cut off, and excitation is cut off; the low potential of the F end enables the triode Q5 to be continuously conducted through the resistor R14 and the diode D13, and as long as the fixed frequency pulse signal output by the oscillating unit does not arrive, the trigger is always in a self-locking reset state of being cut off at the power tube Q2. Only when the next fixed-frequency trigger pulse comes, a new excitation period can be started.

In the voltage regulator provided by the embodiment of the invention, when overcurrent of the power tube occurs due to excitation short circuit, a large voltage drop Uds is generated between the drain electrode and the source electrode of the power tube Q2 by excessive current, the voltage drop Uds is added to the emitting junctions of R14, D13 and Q5 in the feedback circuit, and when the Uds is more than or equal to the sum of the emitting junction of the triode Q5 and the conducting threshold of the diode D13, the triode Q5 is conducted, so that the trigger is immediately turned over, the excitation current is turned off, and the power tube Q2 is protected. When continuous short circuit occurs, short circuit monitoring pulse synchronous with fixed frequency trigger narrow pulse or edge pulse appears in the excitation loop, after overcurrent or short circuit is relieved, the circuit is turned over to be in excitation state under the trigger of next trigger pulse when under voltage.

It should be noted that, in the voltage regulator provided in the embodiment of the present invention, the diode D13 of the trigger feedback unit is used to adjust the start control point of the overcurrent protection, and is also used to prevent the power transistor Q2 from being triggered by a false protection action due to an increase in saturation voltage drop caused by temperature drift, so as to ensure the effectiveness of the trigger. It should be understood that diode D13 may be omitted where the elevated temperature environment allows.

When the output voltage of the generator is greater than or equal to a preset generator voltage threshold value or the power tube is overcurrent, for example, when the excitation winding is short-circuited, the power tube Q2 is cut off, namely reset and self-locked, so that the excitation current is cut off, and the power tube Q2 and the excitation winding are protected; when the output voltage of the generator is smaller than the preset voltage threshold value, if the power tube Q2 is in a cut-off self-locking state at the moment, the power tube Q2 can be switched on through a fixed-frequency trigger pulse signal input to the switch control unit to realize setting and self-locking, and therefore excitation is recovered. Meanwhile, in the process, the feedback unit 3 is also used as an overcurrent detection circuit of the power tube Q2, the conduction internal resistance of the power tube Q2 is also used as an overcurrent sampling resistor, and the switch unit 4 is also used as an overcurrent protection execution circuit, so that the trigger circuit and the overcurrent protection circuit become a multifunctional composite circuit with the same structure, and the multifunctional function of the trigger is realized by an extremely simple circuit structure. The voltage regulator is particularly suitable for a high-reliability fixed-frequency excitation automobile generator voltage regulator.

In a seventh aspect, the present invention provides a voltage regulator, as shown in fig. 7, the voltage regulator similarly includes the third flip-flop, and further includes a freewheeling unit 71, a fifth voltage stabilization unit 72, a sixth voltage stabilization unit 73, a sampling unit 74, an oscillating unit 75, a shaping unit 76, and a reference threshold setting unit 77.

The freewheeling unit 71 is connected to ground and the control end of the trigger, and is configured to form a freewheeling circuit with a load connected between the control end of the trigger (i.e., end F in fig. 7) and ground (i.e., end E in fig. 7), and absorb induced electromotive force generated by the load; the fifth voltage stabilizing unit 72 is connected to the power supply positive electrode, the ground, the oscillating unit 75, the reference threshold setting unit 77 and the comparing unit 1, and is configured to provide a stable voltage for the oscillating unit 75, the reference threshold setting unit 77 and the comparing unit 1; the sampling unit 74 is connected with the positive electrode of the power supply, the ground and the sixth voltage stabilizing unit 73, and is used for providing an overvoltage signal for the non-inverting input end of the comparing unit 1 under the action of the sixth voltage stabilizing unit 73, so that the trigger is reset and self-locked under the triggering of the overvoltage signal, and is used for cutting off the excitation current of the generator; the reference threshold setting unit 77 is connected to the positive electrode of the power supply and the inverting input terminal of the comparing unit 1, and is configured to provide a second threshold voltage to the inverting input terminal of the comparing unit 1; the oscillating unit 75 is connected with the positive pole of the power supply and the shaping unit 76, the shaping unit 76 is connected with the inverting input end of the comparing unit 1, the oscillating unit 75 inputs a narrow pulse to the inverting input end of the comparing unit 1 under the action of the shaping unit 76, and the trigger is set to be in a conducting state of the switching unit 2 and self-locked under the triggering of the narrow pulse and used for switching on the excitation current of the generator.

Each unit in the voltage regulator may have various implementations, which are illustrated below: as shown in fig. 7, in the flip-flop of the voltage regulator, the comparing unit 1 is a comparator a1, the non-inverting input terminal of which is connected to the p3 node, and the inverting input terminal of which is connected to the p1 node; the switch unit 2 is a power tube Q2, the drain of the switch unit is connected with the terminal F, the source is connected with the power voltage of the motor (namely the voltage of the terminal B +), and the grid and the source of the power tube Q2 are also connected with a protection diode D15; the feedback unit 3 comprises a resistor R19 and a limiting diode D18, wherein one end of the resistor R19 is connected with the source electrode of the power tube, and the other end of the resistor R19 is connected with the p3 node. The anode of the limiting diode D18 is connected with the p3 node, and the cathode is connected with the B + end. In the voltage regulator provided by the embodiment of the present invention, the peripheral circuit of the flip-flop is specifically as follows: the freewheeling unit 71 is a diode D2 connected between the terminal E and the terminal F; the fifth voltage stabilization unit 72 includes a voltage stabilization diode D16, a resistor R20, and a pump power supply. Wherein, the Ve node is an output end of the fifth voltage stabilization unit 72, and the Ve voltage is a stabilized voltage which is lower than the positive B + end of the power supply and is opposite to the positive B + end of the power supply; a resistor R20 is connected between the Ve node and the E terminal; the pump power supply is connected with the Ve node, the B + end and the E end, the other output end of the pump power supply is connected with the Vp node, and the voltage of Vp is at least higher than the voltage of the B + end and is a grid-source voltage value which is suitable for the reliable opening and conduction of the field effect transistor. For example, for a 14V system circuit, the output voltage of the pump power supply can be set to 18-22V; the zener diode D16 is connected between the Ve node and the Vc node (i.e., the B + terminal). The sampling unit 74 comprises a resistor R1 and a resistor R2 which are connected in series, a node p4 between the resistors R1 and R2 is connected with the anode of a voltage-stabilizing diode D17 of the sixth voltage-stabilizing unit 73, and the cathode of the D17 is connected with the non-inverting input end of a comparator A1 through a node p 2; the reference threshold setting unit 77 includes resistors R17 and R18, and the voltage of the p5 node between R17 and R18 is a second threshold voltage and is output to the inverting input terminal of the comparator a 1; the shaping unit 76 includes an input capacitor C1, a diode D9, a resistor R12, and a transistor Q3. One end of the input capacitor C1 is connected to the oscillation unit 75, and the other end is connected to the base of the switching tube Q3; the collector of the switching tube Q3 is connected with the p1 node, and the emitter is connected with the Ve node; the anode of the diode D9 is connected with the Ve node, and the cathode is connected with the p6 node; resistor R12 is connected between the p6 node and the Ve node.

The operation of this voltage regulator is described in detail as follows:

the reference threshold setting unit 77 divides a stable voltage between the Ve node and the Vc node (connected to the B + terminal in this embodiment) to provide a constant second threshold voltage to the inverting input terminal of the comparator a 1. The second threshold voltage can be set by adjusting the values of R17 and R18 according to the power requirement of the generator and the parameters of the power tube, and a certain margin range should be reserved on the basis of the conduction saturation voltage drop of the power tube, namely, the second threshold voltage is larger than the conduction saturation voltage drop of the power tube and smaller than the amplitude limiting voltage of an amplitude limiting diode D18, so that the starting control point of overcurrent protection of the power tube is accurately set, and high-precision overcurrent protection is realized. The sampling unit 74 collects the voltage of the positive electrode of the power supply of the generator to be regulated (i.e., the voltage of the B + terminal), and after the voltage is divided by R1 and R2, the voltage of the p4 node is input to the zener diode D17, and then is output to the non-inverting input terminal of the comparator a1 through the p2 node, so as to be compared with the second threshold voltage. Since the input terminal of the comparator a1 uses the Ve node voltage as the reference point, it is easy to understand that, by reasonably setting the magnitudes of R1 and R2 in the sampling unit 74, the reverse conduction voltage of the diode D17 in the sixth voltage stabilizing unit 73, and the magnitude of the second threshold voltage, the magnitude relationship between the voltage of the power source cathode and the preset generator threshold voltage can be indirectly reflected by the sum of the p4 node voltage Up4 and the voltage stabilizing value Uz17 of the voltage stabilizing diode D17, that is, the potential height relationship between (Up4+ Uz17) and the second threshold voltage p5 node voltage Up 5. Upon comparison by comparator a1, the following two results may occur:

(1) when the three potential relationships are Up4+ Uz17 > Up5, that is, when the output voltage of the generator is lower than the preset threshold voltage of the generator, and the narrow pulse does not arrive at the output end of the shaping unit 76, the third flip-flop shown in fig. 7 has two stable states, which are specifically described as follows:

A. steady state of saturated conduction of the power tube Q2: the power transistor Q2 conducts current from the field winding connected between the terminal F + and ground. The saturation voltage drop Uds of the excitation current between the drain and the source is very small, for example, Uds is 0.45V (for description only, and not limited by a numerical value), that is, the source voltage Us ═ UB-Uds ═ UB-0.45V. The p3 node voltage Up3 is made to approach Us by the resistor R19, i.e., Up3 ≈ Us. Since the clipping voltage of the clipping diode D18 of the feedback unit 3 is set to be significantly larger than the value of the saturation voltage drop Uds, the clipping diode D18 is turned off, i.e., the voltage at the p3 node is not affected by the clipping diode D18 at this time.

Since the output voltage of the generator is lower than the preset threshold voltage of the generator, namely the proportional voltage division value UR1 obtained across the resistor R1 in the sampling unit 74 is smaller than the sum of the regulated voltage value Uz of the zener diode D17 and the saturation voltage drop Uds of the power tube Q2, namely UR1 < Uz + Uds. At this time, the zener diode D17 is turned off, that is, the voltage at the node p4 of the sampling signal is not enough to turn on the zener diode D17, and the voltage at the node p2 cannot be pulled down through the zener diode D17, so that the voltage at the node p3 is not affected by the node p4 at this time.

And because the narrow pulse at the output end of the shaping unit 76 does not arrive, the switching tube Q3 of the shaping unit 76 is cut off, and the voltage at the p5 node is not influenced by the switching tube Q3.

And a certain margin range is reserved on the basis of the conduction saturation voltage drop of the power tube due to the size of the second threshold voltage, so that the proportional voltage division value UR17 obtained at two ends of the resistor R17 of the reference threshold setting unit 77 is greater than Uds, namely UR17 is greater than Uds.

It is easy to understand that, at this time, the inverting input terminal of the comparator a1 is controlled by the proportional voltage division value UR17 obtained across the resistor R17, and the non-inverting input terminal of the comparator a1 is controlled by the saturation voltage drop Uds of the power tube Q2. Since UR17 and Uds are both absolute values of voltage between the terminal B + and UB > UR17 > Uds, they are converted into voltage algebraic values with the Ve node voltage as a reference point: that is, the node potential Up5 of p5 is lower than the node voltage Up3 of p3, so that the power tube Q2 is driven to be saturated and conducted by the high-level pump power supply voltage output by the comparator a1, and the state is self-locked through the feedback unit 3.

B. In the steady state that the power tube Q2 is cut off, the potential of the F + end is pulled down by the exciting winding, and the potential of the p3 node is pulled down by the resistor R19. Meanwhile, under the action of the limiter diode D18, the potential of the p3 node is limited, so that the voltage of the non-inverting input terminal of the comparator a1 is lower than that of the inverting input terminal thereof, the comparator a1 outputs a low level, the power tube Q2 is cut off, and is self-locked in the state through the feedback unit 3.

When the narrow pulse output after the oscillation unit 75 passes through the shaping unit 76 comes:

in the case of a, the pulse signal output by the oscillating unit 75 passes through the shaping unit 76 and then the leading edge of the pulse is amplified in a phase inversion manner, and since the capacitor C1 is connected to the emitter-equivalent input resistor of the switching tube Q3 in the form of a differential unit and the capacitor C1 has a small capacity, the switching tube Q3 is turned on only at the time of the steep rising edge of the pulse transmitted by the capacitor C1. The collector of the transistor Q3 generates a very narrow low-level narrow pulse, and during the non-narrow pulse period, i.e. after the narrow pulse, the collector output of the transistor Q3 is in an open-circuit state, i.e. a high-impedance state. When the steep front edge of the pulse transmitted by the capacitor C1 arrives, the rising edge reaches the switching tube Q3 through the capacitor C1 to make it turn on briefly, and the collector of the switching tube Q3 pulls down the potential of the inverting input terminal of the comparator a1 through the p1 node, so that the comparator a1 does not turn over. When the pulse passes through the switch tube Q3 and is cut off, the comparator A1 has no influence, so that the following results can be obtained: when the trigger is self-locked in a power tube conducting state, the narrow pulse or edge pulse input to the comparison unit 1 by the oscillating unit 75 through the shaping unit 76 has no influence on the original state.

For the case B, when the steep front of the pulse transmitted by the capacitor C1 arrives, the rising edge reaches the switching tube Q3 via the capacitor C1 to turn on the switching tube Q3 briefly. The collector of the switch Q3 pulls the voltage at the inverting input of the comparator a1 down to the voltage at the Ve node through the p1 node. Meanwhile, the limiter diode D18 makes the potential of the non-inverting input end of the comparator A1 higher than that of the inverting input end. The comparator a1 outputs the pump power supply unit voltage, and turns on the power tube Q2, so that the exciting current appears.

A strong positive feedback process experienced during this period: the potential of the inverting input terminal of the comparator a1 decreases → the potential of the output terminal of the comparator a1 increases → the gate potential of the power tube Q2 is pulled high → the power tube Q2 turns on to pull high the potential at the point F → the potential at the point F is fed back to the non-inverting input terminal of the comparator a1 via the resistor R19 → the potential of the non-inverting input terminal of the comparator a1 increases → the potential of the output terminal of the comparator a1 keeps high. This is a reaction caused by a negative going narrow pulse applied to the inverting input of comparator a1, causing the flip-flop to flip to the set state where power transistor Q2 is on. Because the on-resistance Rds of the power tube Q2 is extremely small when it is saturated, the saturation voltage drop of the power tube Q2 is extremely small, and the source output of the power tube Q2 is close to the voltage of the power supply terminal B +, which is not enough to make the source voltage of the power tube Q2 lower than the second threshold voltage, i.e., the voltage of the inverting input terminal of the comparator a 1. When the comparator a1 outputs a high voltage, its internal output stage switches on the pump power supply unit voltage Vp, and the flip-flop flips to the on state of the power transistor Q2. Even if the narrow pulse has passed, the switching tube Q3 in the shaping unit 76 is turned off, but the high potential output by the power tube Q2 makes the potential of the non-inverting input terminal of the comparator a1 higher than the second threshold voltage, i.e., the potential of the inverting input terminal of a1, via the resistor R19 of the feedback unit 3, so that the flip-flop continues to be stabilized in the on state of the power tube Q2, i.e., self-locked in the on-state of excitation.

Through the above process, it can be known that: when the output voltage of the generator is lower than the preset threshold voltage of the generator, the trigger can be stably self-locked in a conduction excitation state.

(2) When the potential relationship of the three is that Up4+ Uz17 is not less than Up5, namely the output voltage of the generator is not less than the preset threshold voltage of the generator:

then a negative going overvoltage signal is generated at node p2 when the fixed frequency trigger signal is not present. The overvoltage signal changes in real time along with the output voltage of the generator and belongs to an analog signal, and the diode D17 is used for detecting the analog signal to serve as a reset signal. It should be noted that the second threshold voltage of the p5 node is designed for the start-control point of the power transistor Q2 for overcurrent protection. The voltage of the p5 node is also used as a reference voltage for comparing with an analog quantity reset signal (namely, an overvoltage signal for triggering the power tube of the trigger of the embodiment to cut off and self-lock), the detection of the overvoltage signal is determined by the voltage stabilizing value of the voltage stabilizing diode D17, and this is the key point for simplifying the regulator provided by the embodiment, so that the design of the unit is highly integrated. When the detected overvoltage signal reaches the start-up point, the overvoltage signal is compared as a reset signal in comparator a 1: that is, the voltage of the sampled signal is pulled down by the voltage stabilizing diode D17 and the p2 to the non-inverting input terminal of the comparator a1, so that the potential of the non-inverting input terminal is lower than that of the inverting input terminal, thereby causing a strong positive feedback process, specifically: the potential of the non-inverting input terminal of the comparator a1 decreases, the potential of the inverting input terminal is higher than that of the non-inverting input terminal → the potential of the output terminal of the comparator a1 decreases → the potential of the gate of the power tube Q2 is pulled low → the power tube Q2 is turned off, the potential of the source is pulled low → the potential of the F terminal decreases through the resistor R19, and the potential of the non-inverting input terminal of the comparator a1 decreases. This is a reaction caused by a negative reset signal applied to the non-inverting input of comparator a1, which causes the flip-flop to immediately switch to the reset state where power transistor Q2 is off due to the large amplification of the positive feedback comparator. Even if the output voltage of the generator is already lower than the preset voltage value, the voltage stabilizing diode D17 does not pull down the potential of the non-inverting input end of the comparator a1 any more, but the potential of the source of the power tube Q2 pulled down by the exciting winding of the external unit continues to pull down the potential of the non-inverting input end of the comparator a1 through the R19 of the feedback unit 3, so that the potential is lower than the second threshold voltage, and the power tube Q2 is stabilized in a cut-off state of cutting off the exciting current, that is, the trigger realizes the self-locking in the reset state. When the next constant-frequency trigger signal comes, the negative narrow pulse applied to the inverting input terminal of the comparator A1 causes the circuit to turn over and self-lock again in the setting state of the power tube Q2 conducting excitation.

When continuous overvoltage occurs, although the zener diode D17 will pull down the potential of the non-inverting input terminal of the comparator a1 to be lower than the potential of the inverting input terminal of the comparator a1, the switch Q3 of the shaping unit 76 will pull down the potential of the inverting input terminal of the comparator a1 to be lower than the potential of the non-inverting input terminal thereof at the moment when the constant frequency trigger signal arrives, so that the comparator a1 outputs a high potential, i.e., the voltage output by the pump power supply unit, during the narrow pulse or edge pulse, and the power transistor Q2 is turned on briefly. When the narrow pulse or edge pulse passes, the trigger is reset, the power tube Q2 is cut off, and the excitation loop will generate the "residual current".

When the power tube Q2 is overcurrent, an excessive current will pull down the voltage at the source of the power tube Q2, an excessive voltage drop is generated on the conduction internal resistance Rds between the drain and the source of the power tube Q2, the potential at the non-inverting input end of the comparator a1 is pulled down through the R19 of the feedback unit 3, so that the potential at the non-inverting input end is lower than the second reference threshold potential at the p5 point of the inverting input end, and the control starting point of the overcurrent protection of the power tube Q2 can be set by changing the second threshold voltage. The regulated voltage of the zener diode D18 is greater than the saturation voltage drop of the power transistor Q2 when it is normally turned on, thus causing a strong positive feedback process: the potential of the non-inverting input terminal of the comparator a1 decreases → the potential of the output terminal of the comparator a1 decreases → the gate potential of the power transistor Q2 is pulled low → the power transistor Q2 is turned off, and the source potential also decreases, that is, the potential of the terminal F is pulled low → the potential of the terminal F is transmitted to the potential of the non-inverting input terminal of the comparator a1 through the feedback resistor R19, so that the potential of the non-inverting input terminal of the comparator a1 is kept low → the power transistor Q2 is kept turned off. This is a reaction caused by a negative signal applied to the non-inverting input terminal of a1 due to overcurrent of the power transistor Q2, and the comparator a1 immediately flips the flip-flop to a cut-off state where the power transistor Q2 cuts off excitation in a positive feedback state. The source of the power tube Q2 is pulled down by the external excitation winding, even if the short circuit or the overcurrent is removed, the potential pulled down by the excitation winding of the source of the power tube Q2 is still pulled down by the same-phase input end potential of the comparator a1 through the resistor R19 of the feedback unit 3, so that the power tube Q2 is stabilized in the cut-off state, that is, the cut-off self-locking of the protection function is realized, that is, the trigger reset self-locking caused by the overcurrent of the power tube Q2 is realized. When continuous short circuit occurs to cause continuous overcurrent of the power tube Q2, a short circuit monitoring pulse synchronous with a fixed frequency trigger narrow pulse or an edge pulse appears in an excitation loop, and after the overcurrent or short circuit is relieved, when the trigger of the next trigger pulse arrives, the trigger can be triggered to enable the power tube to be conducted to restart excitation.

When the output voltage of the generator is greater than or equal to the preset voltage threshold value of the regulator or the power tube is in overcurrent, the power tube is cut off, namely reset and self-locked, and when the power tube Q2 is in a cut-off self-locking state, the power tube Q2 is conducted, namely set and self-locked through a constant-frequency trigger signal input to the comparator A1. In addition, a feedback circuit in the trigger is also used as an overcurrent detection circuit, and the trigger is particularly suitable for a high-reliability fixed frequency excitation voltage regulator. Meanwhile, the trigger can also select and match an excitation power tube according to the parameters of the generator so as to achieve the optimal configuration of the regulator and the generator and ensure that the protection function is more accurate and complete.

In an eighth aspect, the present invention further provides a voltage regulator, as shown in fig. 8, which similarly includes the third flip-flop, and further includes: a free-wheeling unit 81, a voltage stabilizing unit 82, a sampling unit 83, an oscillating unit 84, a shaping unit 85, and a reference threshold setting unit 86;

wherein, the follow current unit 81 is connected with the positive pole of the power supply and the switch unit; the voltage stabilizing unit 82 is connected with the power supply positive electrode, the ground, the reference threshold setting unit 86, the oscillating unit 84 and the comparing unit 1, and is used for providing stable voltage for the reference threshold setting unit 86, the oscillating unit 84 and the comparing unit 1; the sampling unit 83 is connected with the positive electrode of the power supply, the ground and the inverting input end of the comparing unit 1, and the reference threshold setting unit 86 is connected with the ground and the non-inverting input end of the comparing unit 1 and is used for providing a first threshold voltage for the non-inverting input end of the comparing unit 1; when the sampling signal voltage is greater than the stabilized voltage value of the reference threshold setting unit 86, namely the first threshold voltage, the trigger is reset to be in a cut-off state of the switch unit and self-locked, and the excitation current of the generator is cut off; the oscillating unit 84 is connected with the ground and the shaping unit 85, the shaping unit 85 is connected with the input end of the switching unit, the oscillating unit 84 inputs narrow pulses to the switching unit under the action of the shaping unit 85, the trigger is set to be in a switching unit conducting state and self-locked under the trigger of the narrow pulses, and the generator exciting current is switched on; and a current limiting resistor is also connected in series between the comparison unit and the switch unit and is used for limiting the current of the output end of the comparison unit.

Each unit in the voltage regulator may have various implementations, which are illustrated below: as shown in fig. 8, in the flip-flop of the voltage regulator, the comparing unit is a comparator a1, the non-inverting input terminal of which is connected to the p4 node, and the inverting input terminal of which is connected to the p2 node. The switch unit comprises a power tube Q2, the grid electrode of the power tube Q2 is connected with the output end of the comparator A1 through a current limiting resistor R5, the source electrode is grounded, namely the E end, and the drain electrode is connected with the control end F end of the trigger. The current limiting resistor is used for limiting the pull-down current of the output end of the comparator to the oscillation unit through the shaping unit, and the phenomena of interference or short circuit and the like between an output signal of the comparison unit and a fixed frequency trigger signal are avoided. The feedback unit comprises a resistor R4 and a transistor Q1. One end of the resistor R4 is connected with the drain F of the power tube Q2, and the other end is connected with the base electrode of the triode Q1; the emitter of the triode Q1 is grounded, i.e. the E terminal, the emitter junction conduction threshold of the triode Q1 is also used for comparing with the saturation voltage drop of the power tube Q2 to serve as the starting control point of the overcurrent protection of the power tube, and the collector of the triode Q1 is connected with the non-inverting input end of the comparator a1, so that the triode Q1 and the resistor R4 jointly form a positive feedback circuit of the comparing unit and the switching unit. In the voltage regulator provided in the embodiment of the present invention, the peripheral circuit of the flip-flop is specifically described as follows:

the freewheeling circuit comprises a diode D2, the anode of which is connected with the end F, the cathode of which is connected with the end D +/B +, and the diode D2 is used for forming a loop with a load connected between the end F and the end D +/B + and absorbing induced electromotive force generated by the load. The reference threshold setting unit 86 includes a resistor R3 and a zener diode D1, wherein one end of the resistor R3 is connected to the power supply terminal, i.e., the Vc node, and the other end is connected to the cathode of the zener diode D1. The anode of the zener diode D1 is grounded. The reference threshold setting unit 86 inputs the voltage value divided by the resistor R3 and the zener diode D1 to the non-inverting input terminal of the comparator a1 via the p4 node. The sampling unit 83 includes resistors R1 and R2 connected in series. Wherein, the end of R1 not connected with R2 is connected with the positive electrode of the power supply (namely, the end D +/B + shown in FIG. 8); the end of R2 not connected with R1 is grounded. The sampling unit 83 inputs the divided voltage between R1 and R2 to the inverting input terminal of the comparator a1 via the p2 node, and the overvoltage signal at the divided node, i.e., the p2 node, is an analog reset signal. The voltage stabilization unit 82 includes a resistor R6 and a voltage stabilization diode D3. One end of the resistor R6 is connected with the D +/B + end, and the other end is connected with the Vc node. The anode of the zener diode D3 is grounded, and the cathode is connected to the Vc node. The oscillating unit 84 is connected to the Vc node and the E terminal, and an output signal of the oscillating unit 84 is a forward narrow pulse signal with a high-level duty ratio of 1% or less, which is used herein for illustration of the working process and is not used as a limitation on the duty ratio. The shaping unit 85 includes a diode D4, the anode of which is connected to the oscillation unit 84, and the cathode of which is connected to the gate of the power transistor Q2 via the p1 node.

the sampling unit 83 collects the power voltage (i.e. the voltage at the B + terminal) of the generator to be regulated, and after dividing the voltage by R1 and R2, inputs the voltage at the p2 node to the inverting input terminal of the comparator a1, so as to compare the voltage with the first threshold voltage input to the non-inverting input terminal of the comparator a 1. It is easy to understand that, by properly setting the R1 and R2 in the sampling unit 83, the magnitude relationship between the voltage of the p2 node and the first threshold voltage can be used to indirectly reflect the magnitude relationship between the voltage of the positive electrode of the power supply and the preset threshold voltage of the generator. The following two results may occur:

(1) if the voltage at the p2 node is less than the first threshold voltage, that is, the power voltage is lower than the preset generator threshold voltage:

the inverting input voltage of comparator a1 is lower than the non-inverting input voltage, and comparator a1 should output a low level of 0 at this time. However, since the comparator a1 and the power transistor Q2 form a flip-flop through the current limiting resistor R5 and the feedback unit, the output state is not determined only by the voltages of the non-inverting input terminal and the inverting input terminal, and the following two cases are specifically described:

A. assuming that the comparator a1 outputs a low level 0, when the fixed-frequency trigger narrow pulse or edge pulse output by the oscillating unit 84 does not arrive, the diode D4 of the shaping unit 85 is turned off, there is no turn-on voltage on the gate of the power transistor Q2, the power transistor Q2 is turned off, and the drain, i.e., the potential of the terminal F is pulled high. The voltage at terminal F is input to the base of the transistor Q1 via the resistor R4 in the feedback unit, and provides current to the base of the transistor Q1. The transistor Q1 is turned on in saturation, and pulls down the potential of the non-inverting input terminal of the comparator a1 via the p3 node to be lower than the potential of the inverting input terminal of the comparator a1, and at this time, the output of the comparator a1 is at low level 0 and is stable in this state. The feedback process specifically includes: the potential of the non-inverting input terminal of the comparator A1 is lowered → the output of the comparator A1 is low 0 → the gate potential of the power tube Q2 is lowered through the current limiting resistor R5 → the cut-off drain potential of the power tube Q2, namely the terminal F voltage is pulled high → the terminal F voltage is transmitted to the base stage of the triode Q1 through the R4, the base potential of the triode Q1 is raised → the collector potential of the triode Q1 is lowered, the potential of the non-inverting input terminal of the comparator A1 is lowered, and therefore the steady state, namely the reset state of self-locking at the cut-off of the power tube is.

B. Assuming that the comparator a1 outputs a high level 1, the power transistor Q2 is turned on, and the drain potential, i.e., the voltage at the F terminal, is pulled to a very low saturation voltage drop, which is lower than the emitter junction turn-on threshold voltage of the transistor Q1 in the feedback unit, so that the transistor Q1 is turned off. Since the precondition is that the potential of the inverting input terminal of the comparator a1 is lower than that of the non-inverting input terminal, the comparator a1 outputs a high level 1, and the power transistor Q2 maintains a conducting state. The feedback unit forms the positive feedback of the comparison unit and the switch unit, and the specific process is as follows: the potential of the non-inverting input end of the comparator A1 rises → the comparator A1 outputs high level → the grid potential of the power tube Q2 rises under the action of the current-limiting resistor R5 → the power tube Q2 is conducted, so that the drain potential, namely the potential of the end F is reduced → the end F is input to the base potential of the triode Q1 through the resistor R4, the base potential is reduced → the collector potential of the triode Q1 is increased, the potential of the non-inverting input end of the comparator A1 is increased, the power tube Q2 is locked in a conducting body, and a steady state, namely a power tube conducting excitation state is formed and is self-locked in the setting state.

In the case of a, that is, when the comparator a1 outputs low level 0, when the narrow pulse comes from the oscillating unit 84, the diode D4 of the fixed-frequency pulse trigger shaping unit 85 is turned on to output a fixed-frequency trigger signal, that is, a fixed-frequency trigger narrow pulse or an edge pulse, a short high-level signal is provided to the gate of the power tube Q2 via the p1 node, the power tube Q2 is immediately saturated and turned on, and the output voltage at the drain, that is, the F-terminal is pulled low, that is, the following strong positive feedback process occurs: the gate potential of the power tube Q2 rises → the drain of the power tube Q2, that is, the potential of the terminal F falls → the terminal F is input to the base potential of the transistor Q1 via the resistor R4, the base potential thereof falls → the collector potential of the transistor Q1 rises, the potential of the non-inverting input terminal of the comparator a1 rises → the output high level of the comparator a1 → the gate potential of the power tube Q2 rises via the current limiting resistor R5, and the flip-flop immediately flips. When the forward trigger narrow pulse passes, D4 of the constant-frequency trigger pulse shaping unit 85 is turned off, that is, the PN junction of the diode D4 is reverse-biased, and the internal resistance is very high, that is, in a high-resistance state: d4 of the constant-frequency trigger pulse shaping unit 85 outputs a high-level narrow pulse or edge pulse, and outputs a high impedance state during a non-narrow pulse or edge pulse; at the moment, the trigger is still kept in a setting state of Q2 conduction excitation through a positive feedback circuit and is self-locked.

According to the above, when the output voltage of the generator is lower than the set value, the trigger is self-locked in a setting state that Q2 is conducted for excitation, and the generator is continuously excited.

(2) If the voltage at the p2 node is greater than or equal to the second threshold voltage, that is, the power supply voltage is greater than or equal to the preset generator threshold voltage:

the inverting input of comparator a1 is at a higher potential than its non-inverting input and comparator a1 outputs a low level of 0. The voltage at the p2 node is an analog signal, and when the voltage at the p2 node is greater than the voltage at the p4 node, i.e., the analog reset signal is amplified by the comparator A1, the following two cases are separately explained:

A. if the constant frequency trigger signal does not arrive, the diode D4 is cut off, the power tube Q2 is cut off, and according to the positive feedback action, the trigger is turned over to be in a power tube Q2 cut-off state, and excitation is cut off immediately. That is, if the output voltage of the generator rises to a preset generator threshold voltage or higher, the trigger can immediately turn over to cut off the exciting current, the phase lag caused by the filter capacitor is not existed on the voltage dividing nodes of R1 and R2 of the sampling unit 83, and the exciting current can be cut off only after the flip time of the trigger, which is far shorter than the delay time caused by the filter capacitor, so that the potential overvoltage and overcurrent hazards in the existing regulator are eliminated, and the regulated voltage is more accurate.

B. If the constant-frequency trigger signals arrive at the same time, the diode D4 is conducted, the power tube Q2 is conducted, and the triode Q1 of the feedback unit is cut off. Since the precondition is that the inverting input of the comparator A1 is equal to or greater than the non-inverting input, the output of the comparator A1 remains at the low level of 0. When the narrow pulse of constant frequency trigger passes, the power tube Q2 is cut off again, the trigger will turn over to the cut-off state of the power tube Q2 and lock itself in the state, and the extremely narrow pulse during which the power tube is briefly turned on is called residual current.

Under the self-locking state of the power tube cut-off, along with power consumption, when the output voltage of the generator is reduced to be lower than the preset threshold voltage of the generator, the potential of the reverse phase input end of the comparator is lower than the potential of the in-phase input end, and a new excitation period starts under the action of the fixed frequency trigger pulse. The start of each excitation is triggered by a fixed-frequency trigger pulse, namely a set signal, and the cut-off of the excitation current is caused by the overturn of a trigger by an overvoltage signal, namely a reset signal. After excitation is cut off, even if the output voltage of the generator is lower than the preset threshold voltage of the generator, the trigger cannot be turned into an excitation state, and a new excitation period cannot be started until the next fixed-frequency trigger pulse comes. Therefore, the excitation frequency at the time of normal adjustment is determined by the oscillation unit 84, regardless of the generator speed, the electrical load, and the sampling unit. And the voltage division node of the sampling unit 83 has no filter capacitor, various interference clutter contained in the node can not be transmitted to the grid of the power tube, the power tube can not be retained in the amplification area, the trigger can not be triggered and overturned by mistake, and the waveform output by the power tube is neat and has no clutter.

The voltage regulator provided by the embodiment of the invention can cut off the exciting current in time when the generator is in overvoltage, and can also perform overcurrent protection on the power tube. The following will specifically explain how the voltage regulator provided by the embodiment of the present invention performs overcurrent protection on the power tube:

when the drain current of the power tube Q2 is overlarge due to factors such as short circuit of an excitation winding, leakage current between carbon brushes, leakage current of a copper ring or short circuit and the like, the drain voltage of the power tube Q2 is increased, the PN junction conduction threshold of the base electrode and the emitter electrode of the triode Q1 is used as a starting control point of overcurrent protection of the power tube, when Uds of the power tube Q2 is increased to be more than or equal to the emission junction conduction threshold of the Q1, base current is provided for the triode Q1 through R4 of a feedback unit, the triode Q1 is in saturated conduction through positive feedback cyclic amplification, the same-phase input end potential of the comparator A1 is immediately pulled down, the comparator A1 outputs low potential 0, and then protection of the power tube Q2 is divided into two conditions:

A. if the fixed frequency trigger signal does not arrive at the moment, the diode D4 is cut off, and when the power tube is in overcurrent, the trigger immediately turns over to cut off the current of the power tube Q2 and is self-locked in a cut-off state. Due to the strong positive feedback effect, the flip time of the trigger is extremely short, the overcurrent can be immediately cut off, and the phenomenon that overcurrent peaks excessively flow through the power tube to damage and heat the power tube due to the fact that overcurrent protection is carried out by a protection unit of a capacitor in the prior art is avoided, and the power tube is not effectively protected. The voltage regulator provided by the embodiment of the invention can protect the power tube from breakdown damage caused by overcurrent heating, even if the overcurrent fault is relieved, when no fixed frequency trigger narrow pulse arrives, the power tube Q2 can not be conducted, and is self-locked in a cut-off state.

B. If a narrow pulse comes from the output of the oscillating unit 84 at this time, the diode D4 is turned on, and the power tube Q2 is turned on briefly. At this time, transistor Q1 is still conducting due to overcurrent, so comparator a1 still outputs low level 0. But the narrow pulse output by the oscillating unit 84 passes immediately, the power tube Q2 returns to cut off, and the flip-flop will flip to the power tube cut-off state and self-lock in that state. During this period, the power tube Q2 will be turned on very briefly, and the pulse for turning on the power tube briefly is a short circuit monitoring pulse, and its duty ratio is related to the width of the fixed frequency triggering narrow pulse and the magnitude of the overcurrent current. Under a certain constant-frequency trigger narrow-pulse duty ratio, the larger the overcurrent or short-circuit current is, the faster the drain voltage exceeds the value, and the smaller the conduction duty ratio of the power tube is. Therefore, if the safety requirement of the power tube is to be met, the duty ratio of the short circuit monitoring pulse may be set to be less than 1%, and is not limited herein as a numerical value.

It should be noted that, during normal regulation, the voltage regulator can be protected as safely whether the voltage regulator operates first and then short-circuits or operates first and then short-circuits. When the over-current and short-circuit faults are relieved, the unit automatically restores to normal operation.

In summary, the voltage regulator provided in the embodiments of the present invention can enable the power tube to be cut off, i.e., reset and self-lock when the output voltage of the generator is greater than or equal to the preset voltage threshold of the voltage regulator, or when the power tube is in overcurrent or the excitation winding is in short circuit, so as to immediately cut off the excitation current or perform overcurrent protection on the power tube. When the power tube is in a cut-off self-locking state, the power tube is switched on, namely is set and self-locked through a constant-frequency trigger pulse signal input to the comparison unit. Meanwhile, the feedback unit is used as an overcurrent detection circuit, and is particularly suitable for a high-reliability fixed-frequency excitation voltage regulator. Meanwhile, the voltage regulator provided by the embodiment of the invention can select and match the excitation power tube according to the parameters of the generator, such as the parameters of the excitation winding, so that the regulator and the generator are more optimally configured, and the protection function is more accurate and perfect.

The above embodiments are only for illustrating the invention and are not to be construed as limiting the invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention, therefore, all equivalent technical solutions also belong to the scope of the invention, and the scope of the invention is defined by the claims.

Claims

1. A voltage regulator, characterized in that the voltage regulator comprises a flip-flop, the flip-flop comprising a comparing unit, a switching unit and a feedback unit;

the comparison unit is connected with the switch unit and used for outputting a first voltage to the switch unit when the non-inverting input end is larger than the voltage of the inverting input end: outputting a second voltage to the switching unit when the non-inverting input terminal is smaller than the voltage of the inverting input terminal;

the switch unit is a power unit, the feedback unit is a positive feedback unit and comprises an overcurrent protection circuit, and the overcurrent protection circuit is used for carrying out overcurrent protection on the switch unit through the comparison unit so that the trigger forms a set reset trigger with an overcurrent protection function;

the voltage regulator also comprises a follow current unit, a voltage stabilizing unit, a sampling unit, an error comparison amplifying unit, an oscillating unit, a shaping unit and a reference threshold setting unit;

2. A voltage regulator, comprising a flip-flop, the flip-flop comprising a switch control unit, a switching unit, and a feedback unit;

the feedback unit is connected with the control end and the input end of the switch control unit, and is used for feeding back the signal of the control end to the input end of the switch control unit:

the switch unit is a power unit, the feedback unit is a positive feedback unit and comprises an overcurrent protection circuit, and the overcurrent protection circuit is used for carrying out overcurrent protection on the switch unit through the switch control unit so that the trigger forms a set reset trigger with an overcurrent protection function;

the voltage regulator further comprises a follow current unit, a first voltage stabilizing unit, a second voltage stabilizing unit, a sampling unit, an oscillating unit and a shaping unit;

the follow current unit is connected with the positive electrode of the power supply and the switch unit; the first voltage stabilizing unit is connected with the positive electrode of the power supply, the ground, the switch control unit and the oscillating unit and is used for providing stable voltage for the switch control unit and the oscillating unit; the sampling unit is connected with the positive electrode of the power supply, the ground and the second voltage stabilizing unit, the second voltage stabilizing unit is connected with the input end of the switch control unit, and the sampling unit provides an overvoltage signal for the input end of the switch control unit under the voltage stabilizing effect of the second voltage stabilizing unit, so that the trigger is reset to be in a cut-off state of the switch unit and is self-locked under the triggering of the overvoltage signal, and the excitation current of the generator is cut off; the oscillating unit is connected with the ground and the shaping unit, the shaping unit is connected with the input end of the switch control unit, the oscillating unit inputs narrow pulses to the switch control unit under the action of the shaping unit, the trigger is set to be in a switch unit conducting state and self-locked under the trigger of the narrow pulses, and the excitation current of the generator is switched on.

3. A voltage regulator, comprising a flip-flop, the flip-flop comprising a switch control unit, a switching unit, and a feedback unit;

the voltage regulator further comprises a follow current unit, a third voltage stabilizing unit, a fourth voltage stabilizing unit, a sampling unit, an oscillating unit and a shaping unit;

4. A voltage regulator, characterized in that the voltage regulator comprises a flip-flop, the flip-flop comprising a comparing unit, a switching unit and a feedback unit;

the comparison unit is connected with the switch unit and used for outputting a first voltage to the switch unit when the non-inverting input end is larger than the voltage of the inverting input end; when the non-inverting input end is smaller than the voltage of the inverting input end, outputting a second voltage to the switch unit:

the feedback unit is connected with the control end and the comparison unit in-phase input end, and is used for feeding back the signal of the control end to the comparison unit in-phase input end:

the voltage regulator further comprises a follow current unit, a fifth voltage stabilizing unit, a sixth voltage stabilizing unit, a sampling unit, an oscillating unit, a shaping unit and a reference threshold setting unit;

5. A voltage regulator, characterized in that the voltage regulator comprises a flip-flop, the flip-flop comprising a comparing unit, a switching unit and a feedback unit;

the voltage regulator further comprises a follow current unit, a voltage stabilizing unit, a sampling unit, an oscillating unit, a shaping unit and a reference threshold setting unit;