CN218920398U - Control guide circuit for rail-to-rail output - Google Patents

Abstract

The utility model provides a control guide circuit for rail-to-rail output, which comprises a constant current generation module, a control guide module and a current limiting resistor, wherein the constant current generation module is used for generating adjustable constant driving current; the control guiding module is used for receiving the PWM control signal and generating the PWM control guiding signal based on the PWM control signal and the constant driving current; the current limiting resistor is used for performing current limiting operation on the PWM control pilot signal. The constant current generation module and the control guide module are arranged, so that the voltage difference between the output voltage and the input voltage can be eliminated, the output current is controllable, the excessive power consumption or the excessive heating value can be effectively avoided, and the working efficiency of the control guide circuit is improved.

Description

Control guide circuit for rail-to-rail output

Technical Field

The utility model relates to the field of circuits, in particular to a control guide circuit for rail-to-rail output.

Background

The control guide PWM signal output generally uses a push-pull circuit to output, a specific push-pull circuit structure is shown in fig. 1, the output voltage amplitude of an emitter of an NPN triode of an upper N lower P type push-pull circuit in fig. 1 is lower than the input voltage amplitude of a base by 0.7V, and the risk of simultaneous conduction of an upper tube and a lower tube possibly occurs in the input voltage signal switching process; in addition, when the voltage of the input signal is low, for example, the output current of the push-pull circuit is too large, the power consumption and the heat productivity of the NPN transistor become large. Therefore, the working efficiency of the existing control pilot circuit is lower.

Therefore, it is desirable to provide a control and guiding circuit for rail-to-rail output to solve the above-mentioned problems.

Disclosure of Invention

The utility model provides a control guide circuit which has no pressure difference and is efficient in operation and is output from rail to rail; the technical problem that the working efficiency of an existing control guide circuit for rail-to-rail output is low is solved.

The utility model provides a control guidance circuit of rail-to-rail output, which comprises:

the constant current generation module is used for generating adjustable constant driving current;

the control guiding module is used for receiving the PWM control signal and generating a PWM control guiding signal based on the PWM control signal and the constant driving current; and

the current limiting resistor is arranged at the output end of the control guiding module and used for carrying out current limiting operation on the PWM control guiding signal.

In the control steering circuit for rail-to-rail output according to the present utility model, the control steering circuit further includes:

and the buffer module is used for buffering the PWM control guide signal.

In the rail-to-rail output control guide circuit, the constant current generation module comprises a first PMOS tube, a second PMOS tube and an adjusting resistor R1, wherein the grid electrode of the first PMOS tube is respectively connected with the grid electrode of the second PMOS tube and the first end of the adjusting resistor R1; the source electrode of the first PMOS tube is connected with the source electrode of the second PMOS tube and a power supply VCC respectively; the drain electrode of the first PMOS tube is connected with the first end of the adjusting resistor R1, and the second end of the adjusting resistor R1 is grounded; and the drain electrode of the second PMOS tube outputs the constant driving current.

In the rail-to-rail output control guide circuit, the constant current generation module comprises a first PNP tube, a second PNP tube and an adjusting resistor R2, wherein the base electrode of the first PNP tube is respectively connected with the base electrode of the second PNP tube and the first end of the adjusting resistor R2; the emitter of the first PNP tube is connected with the emitter of the second PNP tube and a power supply VCC respectively; the collector of the first PNP tube is connected with the first end of the adjusting resistor R2, and the second end of the adjusting resistor R2 is grounded; the collector of the second PNP transistor outputs the constant driving current.

In the rail-to-rail output control guide circuit, the control guide module comprises a switching tube, the control end of the switching tube inputs the PWM control signal, the input end of the switching tube is connected with the output end of the constant current generation module, and the output end of the switching tube is grounded.

In the control guiding circuit for rail-to-rail output of the present utility model, the control guiding circuit further includes a grounding resistor R3, a first end of the grounding resistor R3 is connected to the output end of the constant current generating module, and a second end of the grounding resistor R3 is grounded.

In the rail-to-rail output control guide circuit, the buffer module comprises a third PMOS tube and a fourth NMOS tube, wherein the source electrode of the third PMOS tube is connected with the output of the constant current generation module, the grid electrode of the third PMOS tube is respectively connected with the grid electrode of the fourth NMOS tube and the first end of the blocking resistor R4, and the drain electrode of the third PMOS tube outputs a high-level signal of the PWM control guide signal; the second end of the isolating resistor R4 is grounded; the source electrode of the fourth NMOS tube is connected with the output of the constant current generation module, and the drain electrode of the fourth NMOS tube outputs the low-level signal of the PWM control guide signal.

In the control guiding circuit for rail-to-rail output of the present utility model, the control guiding circuit further includes a grounding resistor R5, a first end of the grounding resistor R5 is connected to the output of the constant current generating module, and a second end of the grounding resistor R5 is grounded.

In the control guiding circuit for rail-to-rail output of the present utility model, the control guiding circuit further includes a grounding resistor R6, a first end of the grounding resistor R6 is connected to the output of the buffer module, and a second end of the grounding resistor R6 is grounded.

In the control steering circuit for rail-to-rail output according to the present utility model, the control steering circuit includes:

and the comparison module is used for generating the PWM control signal based on the reference voltage and the input voltage.

Compared with the prior art, the utility model has the beneficial effects that: the utility model provides a control guide circuit for rail-to-rail output, which can eliminate the pressure difference between output voltage and input voltage through the arrangement of a constant current generation module and a control guide module, and can effectively avoid excessive power consumption or heating value for the output current, thereby improving the working efficiency of the control guide circuit; the technical problem that the working efficiency of an existing control guide circuit for rail-to-rail output is low is effectively solved.

Drawings

FIG. 1 is a schematic diagram of a conventional push-pull circuit structure;

FIG. 2 is a schematic diagram of an embodiment of a rail-to-rail output control steering circuit according to the present utility model;

FIG. 3 is a schematic diagram of a first embodiment of a rail-to-rail output control and steering circuit according to the present utility model;

FIG. 4 is a schematic diagram of a second embodiment of a rail-to-rail output control and guide circuit according to the present utility model;

FIG. 5 is a schematic diagram of a third embodiment of a rail-to-rail output control and steering circuit according to the present utility model;

FIG. 6 is a schematic diagram of a fourth embodiment of a rail-to-rail output control steering circuit according to the present utility model;

fig. 7 is a schematic diagram of a fifth embodiment of a rail-to-rail output control and guide circuit according to the present utility model.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the drawings, like structural elements are denoted by like reference numerals.

The control guide circuit is applied to various charging driving circuits, and because no voltage difference exists between the output voltage and the input voltage, the high-efficiency rail-to-rail output can be realized, and the working efficiency of the control guide circuit is improved.

Referring to fig. 2, fig. 2 is a schematic diagram of an embodiment of a rail-to-rail output control guiding circuit according to the present utility model. The control pilot circuit 10 of the present utility model includes a constant current generation module 11, a control pilot module 12, and a buffer module 13. The constant current generation module 11 is used for generating adjustable constant driving current; the control pilot module 12 is configured to receive the PWM control signal and generate a PWM control pilot signal based on the PWM control signal and the constant driving current; the buffer module 13 is used for buffering the PWM control pilot signal to avoid generating a large current signal (a large current generated by directly loading a driving voltage onto an external small load).

According to the scheme, the constant current generation module 11 and the control guide module 12 are arranged, so that the voltage difference between the output voltage and the input voltage is eliminated, the output current can be controlled, the excessive power consumption or the excessive heating value of the switching tube is avoided, and the working efficiency of the control guide circuit is improved. Meanwhile, the buffer module 13 can buffer the output current in a load manner, so that a large current signal generated when the output load is not connected is avoided. Of course, the buffer module 13 may be set based on the customer's demand selection.

Referring to fig. 3, fig. 3 is a schematic diagram of a first embodiment of a rail-to-rail output control guiding circuit according to the present utility model. The control pilot circuit 30 in the present embodiment includes a constant current generation module 31, a control pilot module 32, a ground resistor R3, and a current limiting resistor R7. The constant current generation module 31 includes a first PMOS transistor Q1, a second PMOS transistor Q2, and an adjusting resistor R1; the grid electrode of the first PMOS tube Q1 is respectively connected with the grid electrode of the second PMOS tube Q2 and the first end of the adjusting resistor R1; the source electrode of the first PMOS tube Q1 is connected with the source electrode of the second PMOS tube Q2 and the power supply VCC respectively; the drain electrode of the first PMOS tube Q1 is connected with the first end of the adjusting resistor R1, and the second end of the adjusting resistor R1 is grounded; the drain electrode of the second PMOS tube Q2 outputs constant driving current.

The control guiding module 32 comprises a switching tube Q3, a control end of the switching tube Q3 inputs PWM control signals, an output end of the switching tube is connected with an output end of the constant current generating module, and an output end of the switching tube is grounded.

The first end of the grounding resistor R3 is connected with the output end of the constant current generation module, and the second end of the grounding resistor R3 is grounded so as to provide a grounding load when the charging circuit is not used.

The current limiting resistor R7 is disposed at the output end of the control guiding module 32, and is used for performing a current limiting operation on the output PWM control guiding signal.

When the control guiding circuit of the embodiment is used, in order to prevent the output from being affected by the working states of the switch tubes (the first PMOS tube and the second PMOS tube), the constant current generation module is set to output constant driving current, the gate voltage of the second PMOS tube is determined by the fixed voltage drop of the gate and the source of the first PMOS tube, the adjusting resistor R1 and the voltage value of the power supply VCC, that is, after the adjusting resistor R1 and the voltage value of the power supply VCC are determined, the drain output current of the second PMOS tube is not changed along with the change of the working states (such as the amplification factor and the like) of the second PMOS tube. Therefore, under the condition that the voltage value of the power supply VCC is determined, the constant driving current output by the constant current generating module can be determined by adjusting the size of the adjusting resistor R1. Thus, when the switching tube Q3 is turned off, the control guiding circuit can output constant driving current which is not influenced by the voltage drop in the second PMOS tube.

In this embodiment, the switching tube Q3 is an NMOS tube, and when the control end (gate) of the switching tube Q3 receives the high level signal, the input end (drain) and the output end (source) of the switching tube Q3 are turned on, and at this time, the drain output of the second PMOS tube is directly grounded, so as to control the pilot circuit to output the low level signal. When the control end of the switching tube Q3 receives the low-level signal, the input end and the output end of the switching tube Q3 are disconnected, and at the moment, the drain electrode of the second PMOS tube is connected to the output end of the control guide circuit and outputs the high-level signal. Therefore, when the control end of the switching tube Q3 receives the PWM control signal, the output end of the control guiding circuit outputs the constant driving current generated by the constant current generating module based on the low level signal interval of the PWM control signal.

Referring to fig. 4, fig. 4 is a schematic diagram of a second embodiment of a rail-to-rail output control guiding circuit according to the present utility model. The control pilot circuit 40 in the present embodiment includes a constant current generation module 41, a control pilot module 42, and a ground resistor R3.

The first difference between this embodiment and the first embodiment of the control guiding circuit is that the constant current generating module 41 of this embodiment includes a first PNP transistor Q4, a second PNP transistor Q5, and an adjusting resistor R2. The base electrode of the first PNP tube Q4 is respectively connected with the base electrode of the second PNP tube Q5 and the first end of the adjusting resistor R2; the emitter of the first PNP tube Q4 is connected with the emitter of the second PNP tube Q5 and the power supply VCC respectively; the collector of the first PNP tube Q4 is connected with the first end of the adjusting resistor R2, and the second end of the adjusting resistor R2 is grounded; the collector of the second PNP transistor Q5 outputs the constant driving current.

In order to prevent the output voltage from being affected by the operating states of the switching transistors (the first PNP transistor Q4 and the second PNP transistor Q5), the constant current generating module 41 is configured to output a constant driving current, and the base voltage of the second PNP transistor Q5 is determined by the fixed voltage drop of the base emitter of the first PNP transistor Q4, the adjusting resistor R2, and the voltage value of the power supply VCC, that is, the collector output current of the second PNP transistor Q5 is not changed along with the change of the operating state (such as the amplification factor) of the second PNP transistor Q5 after the voltage values of the adjusting resistor R2 and the power supply VCC are determined. Therefore, under the condition that the voltage value of the power supply VCC is determined, the constant driving current output by the constant current generating module can be determined by adjusting the size of the adjusting resistor R2.

Referring to fig. 5, fig. 5 is a schematic diagram illustrating a third embodiment of a rail-to-rail output control and guide circuit according to the present utility model. The control pilot circuit 50 in the present embodiment includes a constant current generation module 51, a control pilot module 52, a buffer module 53, and a ground resistor R5.

The structure and the working principle of the constant current generation module 51 and the control guide module 52 are exactly the same as those of the constant current generation module 31 and the control guide module 32 in the first embodiment.

The first end of the grounding resistor R5 is connected to the output end of the constant current generation module 51, and the second end of the grounding resistor R5 is grounded.

The first embodiment of the control guiding circuit is further provided with a buffer module 53, and the buffer module 53 buffers the PWM control guiding signal to avoid that the driving voltage or the driving current is directly loaded on the external load (does current follow), thereby meeting the use needs of various external loads of users.

The buffer module 53 includes a third PMOS transistor Q6, a fourth NMOS transistor Q7, and a blocking resistor R4, where a source of the third PMOS transistor Q6 is connected to an output of the constant current generating module 51, a gate of the third PMOS transistor Q6 is connected to a gate of the fourth NMOS transistor Q7 and a first end of the blocking resistor R4, and a drain of the third PMOS transistor Q6 outputs a high level signal of the PWM control pilot signal; the second end of the isolating resistor R4 is grounded and is used for isolating partial fluctuation interference of the grounding end; the source electrode of the fourth NMOS tube Q7 is connected with the output of the constant current generation module, and the drain electrode of the fourth NMOS tube Q7 outputs a low-level signal of the PWM control guide signal.

In order to reduce the loss, the third PMOS transistor Q6 and the fourth NMOS transistor Q7 may be switching transistors with smaller on-resistance, and of course, corresponding types of transistors may also be used for the third PMOS transistor Q6 and the fourth NMOS transistor Q7.

When the PWM control pilot signal output by the control pilot module 52 is a high level signal (e.g., +12v), the gate voltage of the third PMOS transistor Q6 is lower than the source voltage of the third PMOS transistor Q6, the third PMOS transistor Q6 is turned on, and the drain of the third PMOS transistor Q6 outputs the high level signal of the PWM control pilot signal. At this time, the gates of the third PMOS transistor Q6 and the fourth NMOS transistor Q7 are both low level with respect to the PWM control pilot signal, so the fourth NMOS transistor Q7 is turned off.

When the PWM control pilot signal outputted from the control pilot module 52 is a low level signal (e.g., -12 v), the gate voltage of the fourth NMOS transistor Q7 is higher than the source voltage of the fourth NMOS transistor Q7, the fourth NMOS transistor Q7 is turned on, and the drain of the fourth NMOS transistor Q7 outputs the low level signal of the PWM control pilot signal. The gates of the third PMOS transistor Q6 and the fourth NMOS transistor Q7 are both high level with respect to the PWM control pilot signal, so the third PMOS transistor Q6 is turned off.

The buffer module 53 performs a cut-off buffer operation on the constant driving current, and performs a current following function through the internal resistances of the third PMOS transistor Q6 and the fourth NMOS transistor Q7, so that the larger constant driving current is prevented from being directly loaded on an external load. Thus, when the PWM control pilot signal is a high level signal, the buffer module 53 can be used as an active load, so as to realize current following and avoid large current caused by instant conduction.

Referring to fig. 6, fig. 6 is a schematic diagram of a fourth embodiment of a rail-to-rail output control guiding circuit according to the present utility model. The control pilot circuit 60 in the present embodiment includes a constant current generation module 61, a control pilot module 62, a buffer module 63, and a ground resistor R6.

The structure and the working principle of the constant current generating module 61 and the control guiding module 62 are identical to those of the constant current generating module 51 and the control guiding module 52 in the third embodiment.

The first end of the grounding resistor R6 in this embodiment is connected to the output of the buffer module 63, and the second end of the grounding resistor R6 is grounded.

The grounding resistor R6 of the embodiment is disposed at the drain ends of the third PMOS transistor Q6 and the fourth NMOS transistor Q7, so that the gates, the drains and the sources of the third PMOS transistor Q6 and the fourth NMOS transistor Q7 are directly or indirectly grounded, the phenomenon that the pins of the switching transistor are suspended does not exist, and the problem that the switching transistor is easily interfered by the outside or radiates to the outside during operation is avoided.

Referring to fig. 7, fig. 7 is a schematic diagram of a fifth embodiment of a rail-to-rail output control and guide circuit according to the present utility model. The control pilot circuit 70 of the present embodiment includes a constant current generation module 71, a control pilot module 72, a buffer module 73, and a comparison module 74.

The constant current generation module 71, the control guide module 72, and the buffer module 73 are identical to the structures and the working principles of the constant current generation module 51, the control guide module 52, and the buffer module 53 in the third embodiment.

On the basis of the third embodiment, the control steering circuit 70 of the present embodiment further includes a comparison module 71, and the comparison module 74 is configured to generate the PWM control signal based on the reference voltage and the input voltage.

The negative input terminal of the comparison module 74 inputs the reference voltage REF, the positive input terminal of the comparison module 74 inputs the input voltage VIN, and the output terminal of the comparison module 74 outputs the PWM control signal. Specifically, the output terminal outputs a high level signal of the PWM control signal when the input voltage VIN is greater than or equal to the reference voltage REF, and outputs a low level signal of the PWM control signal when the input voltage VIN is less than the reference voltage REF.

The comparison module 74 is configured to preferably avoid high level signal fluctuations of the PWM control signal caused by forward fluctuations of the input voltage, thereby outputting a stable PWM control signal.

The rail-to-rail output control guide circuit has low requirement on the slew rate of the input PWM control signal, can output the rail-to-rail PWM control guide signal, does not need to consider the pressure difference in the switching tube, can control the load capacity by adjusting the constant driving current generated by the constant current generation module, and has strong driving capacity and low cost.

The rail-to-rail output control steering circuit of the present utility model can use common power supplies in the market, such as 12V units, and does not require custom-made unusual power supplies based on output voltage, such as 12.7V power supplies, etc.

Through setting up the comparison module, reduced the requirement to input voltage (drive signal), better avoided PWM control signal to take place to vibrate, realized simply.

The utility model provides a control guide circuit for rail-to-rail output, which can eliminate the pressure difference between output voltage and input voltage through the arrangement of a constant current generation module and a control guide module, and can effectively avoid excessive power consumption or heating value for the output current, thereby improving the working efficiency of the control guide circuit; the technical problem that the working efficiency of an existing control guide circuit for rail-to-rail output is low is effectively solved.

In summary, although the present utility model has been described in terms of the preferred embodiments, the preferred embodiments are not limited to the above embodiments, and various modifications and changes can be made by one skilled in the art without departing from the spirit and scope of the utility model, and the scope of the utility model is defined by the appended claims.

Claims (10)

1. A control steering circuit for rail-to-rail output, comprising:

the constant current generation module is used for generating adjustable constant driving current;

the control guiding module is used for receiving the PWM control signal and generating a PWM control guiding signal based on the PWM control signal and the constant driving current; and

the current limiting resistor is arranged at the output end of the control guiding module and used for carrying out current limiting operation on the PWM control guiding signal.

2. The rail-to-rail output control steering circuit of claim 1, further comprising:

and the buffer module is used for buffering the PWM control guide signal.

3. The rail-to-rail output control and guide circuit according to claim 1, wherein the constant current generation module comprises a first PMOS tube, a second PMOS tube and an adjusting resistor R1, and the gate of the first PMOS tube is connected with the gate of the second PMOS tube and the first end of the adjusting resistor R1, respectively; the source electrode of the first PMOS tube is connected with the source electrode of the second PMOS tube and a power supply VCC respectively; the drain electrode of the first PMOS tube is connected with the first end of the adjusting resistor R1, and the second end of the adjusting resistor R1 is grounded; and the drain electrode of the second PMOS tube outputs the constant driving current.

4. The rail-to-rail output control and guide circuit according to claim 1, wherein the constant current generation module comprises a first PNP transistor, a second PNP transistor and an adjusting resistor R2, and a base of the first PNP transistor is connected to a base of the second PNP transistor and a first end of the adjusting resistor R2, respectively; the emitter of the first PNP tube is connected with the emitter of the second PNP tube and a power supply VCC respectively; the collector of the first PNP tube is connected with the first end of the adjusting resistor R2, and the second end of the adjusting resistor R2 is grounded; the collector of the second PNP transistor outputs the constant driving current.

5. The rail-to-rail output control guide circuit according to claim 3 or 4, wherein the control guide module comprises a switching tube, a control end of the switching tube inputs the PWM control signal, an input end of the switching tube is connected with an output end of the constant current generation module, and an output end of the switching tube is grounded.

6. The rail-to-rail output control steering circuit of claim 5, further comprising a ground resistor R3, a first end of the ground resistor R3 being connected to the output of the constant current generation module, a second end of the ground resistor R3 being grounded.

7. The rail-to-rail output control guide circuit according to claim 2, wherein the buffer module comprises a third PMOS and a fourth NMOS, a source of the third PMOS is connected to an output of the constant current generation module, a gate of the third PMOS is connected to a gate of the fourth NMOS and a first end of the blocking resistor R4, respectively, and a drain of the third PMOS outputs a high level signal of the PWM control guide signal; the second end of the isolating resistor R4 is grounded; the source electrode of the fourth NMOS tube is connected with the output of the constant current generation module, and the drain electrode of the fourth NMOS tube outputs the low-level signal of the PWM control guide signal.

8. The rail-to-rail output control steering circuit of claim 7, further comprising a ground resistor R5, a first end of the ground resistor R5 being connected to the output of the constant current generation module, a second end of the ground resistor R5 being grounded.

9. The rail-to-rail output control steering circuit of claim 7, further comprising a ground resistor R6, a first end of the ground resistor R6 being connected to the output of the buffer module, a second end of the ground resistor R6 being grounded.

10. The rail-to-rail output control steering circuit of claim 1, wherein the control steering circuit comprises:

and the comparison module is used for generating the PWM control signal based on the reference voltage and the input voltage.

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