CN114189139B

CN114189139B - Slow start circuit, power supply system and electronic equipment

Info

Publication number: CN114189139B
Application number: CN202111462260.7A
Authority: CN
Inventors: 赵冬亮
Original assignee: Syrius Technology Shenzhen Co Ltd
Current assignee: Syrius Technology Shenzhen Co Ltd
Priority date: 2021-12-02
Filing date: 2021-12-02
Publication date: 2024-02-20
Anticipated expiration: 2041-12-02
Also published as: CN114189139A

Abstract

The invention discloses a slow start circuit, a power supply system and electronic equipment, and belongs to the technical field of electronic equipment. The slow start circuit includes: the device comprises a main loop switch module, a main loop switch control module, a slow starting current control module and a slow starting loop switch module; when the switch control signal of the power supply system is at a high level for controlling the power supply of the power supply system to be turned on, the slow start loop switch is closed firstly, and constant current pre-supplies power to the load circuit, so that the secondary voltage is higher and higher, when the secondary voltage reaches a preset voltage threshold value, the main loop switch is closed, and at the moment, the power supply system is completely turned on to supply power to the load circuit; when the power supply system switch control signal is at a low level for controlling the power supply of the power supply system to be closed, the main loop switch and the slow start switch are both closed rapidly. Therefore, overcurrent protection of a power supply system caused by overlarge current at the moment of electrification can be effectively prevented, and a switching device is ignited or a joint wire harness is damaged due to surge impact.

Description

Slow start circuit, power supply system and electronic equipment

Technical Field

The present invention relates to the field of electronic devices, and in particular, to a slow start circuit, a power supply system, and an electronic device.

Background

In the electronic equipment, because the capacitance of the load circuit is more, if the power supply system of the electronic equipment directly powers on the load circuit, the power supply system can be protected from overcurrent, and a switching device is ignited or a joint wire harness is damaged due to surge impact. There is a need for a slow start circuit solution.

Disclosure of Invention

Accordingly, an objective of the embodiments of the present invention is to provide a slow start circuit, a power supply system, and an electronic device, so as to solve the technical problem that in the current electronic device, because the capacitance of a load circuit is large, if the power supply system of the electronic device directly powers on the load circuit, the power supply system may be protected from overcurrent, a switching device is ignited, or a joint harness is damaged due to surge impact.

The technical scheme adopted by the invention for solving the technical problems is as follows:

according to an aspect of an embodiment of the present invention, there is provided a slow start circuit applied to a power supply system, the slow start circuit including: the device comprises a main loop switch module, a main loop switch control module, a slow starting current control module and a slow starting loop switch module;

the main loop switch module comprises a main loop switch unit and a secondary voltage feedback unit; the power input end of the main loop switch unit is connected with the power supply of the power supply system, the power output end of the main loop switch unit is respectively connected with the input end of the secondary voltage feedback unit and the load circuit, and the input control end of the main loop switch unit is connected with the output end of the main loop switch control module and is used for starting or stopping the power supply of the power supply system under the control of the main loop switch control module; the output end of the secondary voltage feedback unit is connected with the first input end of the main loop switch control module and is used for feeding secondary voltage back to the main loop switch control module;

The second input end of the main loop switch control module is connected with a power supply system switch control signal and is used for controlling the main loop switch module to be turned on when the secondary voltage reaches a preset voltage threshold under the control of the power supply system switch control signal, and controlling the main loop switch module to be turned off when the secondary voltage does not reach the preset voltage threshold;

the input end of the slow starting current control module is connected with the switch control signal of the power supply system, and the output end of the slow starting current control module is connected with the input end of the slow starting loop switch module and is used for controlling the slow starting loop switch module to be turned on or turned off according to the switch control signal of the power supply system;

the slow start loop switch module comprises a constant current control unit and a slow start loop switch unit; the constant current control unit is respectively connected with a power supply of the power supply system and the slow start loop switch unit, and the slow start loop switch unit is also respectively connected with the input end of the secondary voltage feedback unit and the load circuit; the slow-start loop switch module is used for opening or closing a slow-start loop under the control of the slow-start current control module, and supplying power to the load circuit in advance by constant current when the slow-start loop is opened, so that the main loop switch control module controls the main loop switch module to be opened when the secondary voltage rises to the preset voltage threshold.

Optionally, the main loop switching unit includes a first switching element, a first resistor, and a second resistor;

the first switch element comprises a first P-channel MOS tube, the source electrode of the first P-channel MOS tube is respectively connected with the power supply of the power supply system and one end of the first resistor, the grid electrode of the first P-channel MOS tube is respectively connected with the other end of the first resistor and one end of the second resistor, the drain electrode of the first P-channel MOS tube is respectively connected with the input end of the secondary voltage feedback unit and the load circuit, and the other end of the second resistor is connected with the output end of the main loop switch control module.

Optionally, the secondary voltage feedback unit includes a third resistor, one end of the third resistor is connected with the drain electrode of the first P-channel MOS transistor and the load circuit, and the other end of the third resistor is connected with the first input end of the main loop switch control module.

Optionally, the main loop switch control module comprises a first stage switch unit, a second stage switch unit, a reference voltage source and a first signal amplifying unit; the first-stage switch unit is respectively connected with the power supply system switch control signal and the second-stage switch unit, the second-stage switch unit is also connected with the other end of the third resistor and the reference voltage source, the reference voltage source is also connected with the first signal amplifying unit, and the output end of the first signal amplifying unit is connected with the input control end of the main loop switch unit; the first-stage switch unit is used for controlling the second-stage switch unit to start working when the power supply system switch control signal is an on signal, and controlling the second-stage switch unit to stop working when the power supply system switch control signal is an off signal; and the second-stage switch unit is used for controlling the reference voltage source to output a low-level signal when the secondary voltage reaches a preset voltage threshold value so as to control the first signal amplifying unit to start working and further control the main loop switch module to start the power supply of the power supply system to supply power for the load circuit.

Optionally, the first stage switching unit includes a second switching element, a fourth resistor and a fifth resistor, where the second switching element includes a first PNP type triode, one end of the fourth resistor is connected with the power supply system switch control signal, the other end of the fourth resistor is connected with one end of the fifth resistor and the base of the first PNP type triode, the other end of the fifth resistor and the collector of the first PNP type triode are grounded, and the emitter of the first PNP type triode is connected with the other end of the third resistor and the second stage switching unit, respectively;

the second-stage switch unit comprises a sixth resistor and a capacitor, wherein one end of the sixth resistor is respectively connected with the emitter of the first PNP triode, the other end of the third resistor, one end of the capacitor and the voltage input end of the reference voltage source, and the other end of the sixth resistor and the other end of the capacitor are grounded;

the voltage output end of the reference voltage source is connected with the first signal amplifying unit, and the grounding end of the reference voltage source is grounded;

the first signal amplifying unit comprises a first amplifying element, a seventh resistor and an eighth resistor, the first amplifying element comprises a second PNP type triode, one end of the seventh resistor is connected with the voltage output end of the reference voltage source, the other end of the seventh resistor is respectively connected with one end of the eighth resistor and the base electrode of the second PNP type triode, the other end of the eighth resistor is respectively connected with the other end of the second resistor and the emitter electrode of the second PNP type triode, and the collector electrode of the second PNP type triode is grounded.

Optionally, the slow start current control module includes a second signal amplifying unit, the second signal amplifying unit includes a second amplifying element, a ninth resistor and a tenth resistor, the second amplifying element includes an NPN type triode, one end of the ninth resistor is connected with the power supply system switch control signal, the other end of the ninth resistor is connected with a base electrode of the NPN type triode and one end of the tenth resistor respectively, an emitter electrode of the NPN type triode and the other end of the tenth resistor are grounded, and a collector electrode of the NPN type triode is connected with an input end of the slow start loop switch module.

Optionally, the slow start loop switch unit includes a third switch element, an eleventh resistor and a twelfth resistor, where the third switch element includes a second P-channel MOS transistor; the constant current control unit comprises a third PNP triode, a thirteenth resistor and a fourteenth resistor; one end of the eleventh resistor is connected with the collector of the NPN triode, the other end of the eleventh resistor is respectively connected with the collector of the third PNP triode, one end of the twelfth resistor and the grid electrode of the second P channel MOS tube, the other end of the twelfth resistor is respectively connected with one end of the thirteenth resistor, one end of the fourteenth resistor and the source electrode of the second P channel MOS tube, the drain electrode of the second P channel MOS tube is respectively connected with one end of the third resistor and the load circuit, the other end of the thirteenth resistor is respectively connected with the power supply of the power supply system and the emitter of the third PNP triode, and the other end of the fourteenth resistor is connected with the base electrode of the third PNP triode.

Optionally, when the switch control signal of the power supply system is at a high level, the base electrode of the NPN triode is at a high level, so that the NPN triode works in a conducting state, and thus current flows from the power supply of the power supply system through the thirteenth resistor, the twelfth resistor and the eleventh resistor, so that the third PNP triode works in a conducting state, the second P-channel MOS tube works in a conducting state, and the power supply of the power supply system supplies constant current to the load circuit through the thirteenth resistor and the second P-channel MOS tube;

when the switch control signal of the power supply system is high, the base electrode of the first PNP type triode is high, so that the first PNP type triode works in a cut-off state, the second stage switch unit starts to work, the secondary voltage is divided by the third resistor and the sixth resistor and then charges the capacitor through the sixth resistor, when the secondary voltage reaches the preset voltage threshold, the capacitor controls the reference voltage source to output a low-level signal to the base electrode of the second PNP type triode through the seventh resistor after the secondary voltage reaches the preset voltage threshold, the second PNP type triode works in a conduction state, current flows from the power supply of the power supply system through the first resistor and the second resistor, so that the first P channel MOS tube works in the conduction state, and the power supply of the power supply system supplies power to the load circuit through the first P channel MOS tube.

According to another aspect of the embodiment of the present invention, there is provided a power supply system including the above-described slow start circuit.

According to still another aspect of the embodiment of the present invention, there is provided an electronic device including the above-described soft start circuit.

The slow start circuit, the power supply system and the electronic equipment provided by the embodiment of the invention comprise a main loop switch module, a main loop switch control module, a slow start current control module and a slow start loop switch module; when the switch control signal of the power supply system is at a high level for controlling the power supply of the power supply system to be turned on, the slow start loop switch is closed firstly, and constant current pre-supplies power to the load circuit, so that the secondary voltage is higher and higher, when the secondary voltage reaches a preset voltage threshold value, the main loop switch is closed, and at the moment, the power supply system is completely turned on to supply power to the load circuit; when the power supply system switch control signal is at a low level for controlling the power supply of the power supply system to be closed, the main loop switch and the slow start switch are both closed rapidly. When the power supply system powers on a load, the load circuit is powered on in constant current through the slow start loop, and when the secondary voltage reaches a preset voltage threshold value, the main loop switch is closed again, so that overcurrent protection of the power supply system caused by overlarge current at the moment of power on can be effectively prevented, and a switching device is ignited or a joint wire harness is damaged due to surge impact.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic diagram of a slow start circuit according to an embodiment of the present invention;

fig. 2 is a schematic circuit connection diagram of an implementation manner of a soft start circuit according to an embodiment of the present invention.

Detailed Description

It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

In the following description, suffixes such as "module", "element" or "unit" for representing elements are used only for facilitating the description of the present invention, and have no specific meaning per se. Thus, "module," "element," or "unit" may be used in combination.

Example 1

In order to solve the technical problem that in the current electronic device, because the capacitance of the load circuit is more, if the power supply system of the electronic device directly powers on the load circuit, the power supply system may be over-current protected, and the switching device is ignited or the joint harness is damaged due to surge impact, the embodiment provides a slow start circuit, and please refer to fig. 1, fig. 1 is a schematic diagram of an implementation manner of the slow start circuit provided by the embodiment of the invention. The slow start circuit comprises a main loop switch module 1, a main loop switch control module 2, a slow start current control module 3 and a slow start loop switch module 4.

The main loop switch module 1 comprises a main loop switch unit and a secondary voltage VCC_M feedback unit; the power input end of the main loop switch unit is connected with the power VCC of the power supply system, the power output end of the main loop switch unit is respectively connected with the input end of the secondary voltage VCC_M feedback unit and the load circuit, and the input control end of the main loop switch unit is connected with the output end of the main loop switch control module 2 and is used for starting or stopping the power VCC of the power supply system under the control of the main loop switch control module 2; the output end of the secondary voltage VCC_M feedback unit is connected with the first input end of the main loop switch control module 2 and is used for feeding the secondary voltage VCC_M back to the main loop switch control module 2.

Specifically, the specific circuit structure of the load circuit, which is not shown in fig. 1, may vary according to the electronic device to which the slow start circuit is applied, and the specific circuit structure is not limited in this embodiment. The main loop switch module 1 is configured to turn on or off the power VCC of the power supply system under the control of the main loop switch control module 2, and feedback a secondary voltage vcc_m to the main loop switch control module 2 through a secondary voltage vcc_m feedback unit, so that the main loop switch control module 2 controls the on and off of the main loop switch module 1 according to the secondary voltage vcc_m.

In one embodiment, please refer to fig. 2, fig. 2 is a schematic circuit diagram illustrating a circuit connection of one embodiment of a slow start circuit according to an embodiment of the present invention. The main loop switching unit includes a first switching element, a first resistor R1, and a second resistor R5.

Specifically, the first switching element may be a P-channel MOS transistor, a relay, a dc contactor, or other types of switching elements, so long as the function of the first switching element can be implemented, and the specific type of the first switching element is not limited in this embodiment.

Optionally, the first switching element includes a first P-channel MOS transistor Q1, a source of the first P-channel MOS transistor Q1 is connected to a power VCC of the power supply system and one end of the first resistor R1, a gate of the first P-channel MOS transistor Q1 is connected to another end of the first resistor R1 and one end of the second resistor R5, a drain of the first P-channel MOS transistor Q1 is connected to an input end of the secondary voltage vcc_m feedback unit and the load circuit, and another end of the second resistor R5 is connected to an output end of the main loop switch control module 2.

Specifically, the specific circuit structure of the load circuit is not shown in fig. 2, and may vary according to the electronic device to which the slow start circuit is applied, and the specific circuit structure is not limited in this embodiment. The first P-channel MOS transistor Q1 realizes the on and off actions of the power VCC of the power supply system. Optionally, the first P-channel MOS transistor Q1 is a low internal resistance P-channel MOS transistor, so as to reduce power consumption of the main loop switch unit. The first resistor R1 and the second resistor R5 divide the power VCC of the power supply system, so as to ensure that the first P-channel MOS transistor Q1 is safely turned on or off.

In an embodiment, referring to fig. 2, the secondary voltage vcc_m feedback unit includes a third resistor R7, one end of the third resistor R7 is connected to the drain of the first P-channel MOS transistor Q1 and the load circuit, and the other end of the third resistor R7 is connected to the first input end of the main loop switch control module 2.

Specifically, the third resistor R7 feeds back the secondary voltage vcc_m to the main loop switch control module 2, so that the main loop switch control module 2 controls the on and off of the main loop switch module 1 according to the secondary voltage vcc_m.

The second input end of the main loop switch control module 2 is connected with a power supply system switch control signal, and is used for controlling the main loop switch module 1 to be turned on when the secondary voltage vcc_m reaches a preset voltage threshold under the control of the power supply system switch control signal, and controlling the main loop switch module 1 to be turned off when the secondary voltage vcc_m does not reach the preset voltage threshold.

Specifically, the two input ends of the main loop switch control module 2 are respectively connected with the output end of the secondary voltage vcc_m feedback unit and a power supply system switch control signal, so that under the control of the power supply system switch control signal, when the secondary voltage vcc_m reaches a preset voltage threshold, the main loop switch module 1 is controlled to be turned on, and when the secondary voltage vcc_m does not reach the preset voltage threshold, the main loop switch module 1 is controlled to be turned off.

In one embodiment, the main loop switch control module 2 includes a first stage switch unit, a second stage switch unit, a reference voltage source U1, and a first signal amplifying unit; the first-stage switch unit is respectively connected with the switch control signal of the power supply system and the second-stage switch unit, the second-stage switch unit is also connected with the other end of the third resistor R7 and the reference voltage source U1, the reference voltage source U1 is also connected with the first signal amplifying unit, and the output end of the first signal amplifying unit is connected with the input control end of the main loop switch unit; the first-stage switch unit is used for controlling the second-stage switch unit to start working when the power supply system switch control signal is an on signal, and controlling the second-stage switch unit to stop working when the power supply system switch control signal is an off signal; the second stage switch unit is configured to control the reference voltage source U1 to output a low level signal when the secondary voltage vcc_m reaches a preset voltage threshold, so as to control the first signal amplifying unit to start working, and further control the main loop switch module 1 to start the power VCC of the power supply system, so as to supply power to the load circuit.

Specifically, the first stage switch unit is further configured to control the second stage switch unit to maintain a non-working state when the power supply system switch control signal is absent. When the second-stage switch unit does not work, the reference voltage source U1 outputs a high-level signal to control the first signal amplifying unit to also not work, so as to further control the main loop switch module 1 to keep the power VCC of the power supply system in a closed state, and not to supply power to the load circuit.

In one embodiment, referring to fig. 2, the first stage switching unit includes a second switching element, a fourth resistor R13, and a fifth resistor R14.

Specifically, the second switching element may be a PNP transistor, a P-channel MOS transistor, or other types of switching elements, so long as the function of the second switching element can be implemented, and the specific type of the second switching element is not limited in this embodiment.

Optionally, the second switching element includes a first PNP type triode Q6, one end of the fourth resistor R13 is connected with the power supply system switch control signal, the other end of the fourth resistor R13 is connected with one end of the fifth resistor R14 and the base of the first PNP type triode Q6, the other end of the fifth resistor R14 and the collector of the first PNP type triode Q6 are grounded, and the emitter of the first PNP type triode Q6 is connected with the other end of the third resistor R7 and the second stage switching unit.

Specifically, when the power supply system switch control signal is a low level signal for controlling the power VCC of the power supply system to be turned off, the base electrode of the first PNP transistor Q6 is connected to a low level through the fourth resistor R13, so that the first PNP transistor Q6 works in a conducting state, and the other end of the third resistor R7 is connected to the ground through the first PNP transistor Q6, so as to control the second-stage switch unit to stop working; when the power supply system switch control signal is a high level signal for controlling the power supply VCC of the power supply system to be turned on, the base electrode of the first PNP type triode Q6 is connected with a high level through the fourth resistor R13, so that the first PNP type triode Q6 works in a cut-off state, the other end of the third resistor R7 is disconnected with the ground, and the second-stage switch unit is controlled to start working; when the switch control signal of the power supply system is absent, the base electrode of the first PNP type triode Q6 is grounded through the fifth resistor R14, so that the first PNP type triode Q6 works in a conducting state, and the other end of the third resistor R7 is connected with the ground through the first PNP type triode Q6, so that the second-stage switch unit is controlled to be kept in a non-working state.

The second-stage switch unit comprises a sixth resistor R12 and a capacitor C1, one end of the sixth resistor R12 is respectively connected with the emitter of the first PNP triode Q6, the other end of the third resistor R7, one end of the capacitor C1 and the voltage input end of the reference voltage source U1, and the other end of the sixth resistor R12 and the other end of the capacitor C1 are grounded.

Specifically, the sixth resistor R12 and the capacitor C1 are both connected between the emitter and the collector of the first PNP type transistor Q6, so that the second stage switching unit formed by the sixth resistor R12 and the capacitor C1 stops working when the first PNP type transistor Q6 is turned on, and starts working when the first PNP type transistor Q6 is turned off. When the second stage switch unit starts to work, the secondary voltage vcc_m is divided by the third resistor R7 and the sixth resistor R12, and then charges the capacitor C1 through the sixth resistor R12, and when the secondary voltage vcc_m reaches a preset voltage threshold and the capacitor C1 is charged, the reference voltage source U1 is controlled to output a low level signal to control the first signal amplifying unit to start to work, so as to further control the main loop switch module 1 to start the power VCC of the power supply system and supply power to the load circuit. When the second stage switch unit stops working, the secondary voltage vcc_m fed back through the third resistor R7 is grounded through the first PNP transistor Q6, so that the reference voltage source U1 outputs a high level signal to control the first signal amplifying unit to stop working, so as to further control the main loop switch module 1 to turn off the power VCC of the power supply system and stop supplying power to the load circuit. The resistance values of the third resistor R7 and the sixth resistor R12 are adjusted, so that the starting voltage of the main loop switch unit can be adjusted, the secondary voltage VCC_M value after slow start can be flexibly set, and the ignition phenomenon of a switch device is avoided. The capacitor C1 can realize the delay on and delay off of the main loop switch unit.

The voltage output end of the reference voltage source U1 is connected with the first signal amplifying unit, and the grounding end of the reference voltage source U1 is grounded.

Specifically, the reference voltage source U1 controls the main loop switch unit to be turned on or off through the first signal amplifying unit according to the control of the second stage switch unit. When the power supply system switch control signal is high level and the secondary voltage VCC_M reaches a preset voltage threshold, feedback is accurately made, and the main loop switch module 1 is opened.

The first signal amplifying unit includes a first amplifying element, a seventh resistor R10, and an eighth resistor R8.

Specifically, the first amplifying element may be a PNP transistor, a P-channel MOS transistor, or other types of amplifying elements, so long as the function of the first amplifying element can be implemented, and the specific type of the first amplifying element is not limited in this embodiment.

Optionally, the first amplifying element includes a second PNP type triode Q5, one end of the seventh resistor R10 is connected to the voltage output end of the reference voltage source U1, the other end of the seventh resistor R10 is connected to one end of the eighth resistor R8 and the base of the second PNP type triode Q5, the other end of the eighth resistor R8 is connected to the other end of the second resistor R5 and the emitter of the second PNP type triode Q5, and the collector of the second PNP type triode Q5 is grounded.

Specifically, when the base electrode of the second PNP transistor Q5 is connected to the low level through the seventh resistor R10, the second PNP transistor Q5 is operated in a conducting state, and amplifies the signal output by the reference voltage source U1, so as to ensure that the main loop switch module 1 is completely turned on or turned off.

The input end of the slow starting current control module 3 is connected with the switch control signal of the power supply system, and the output end of the slow starting current control module 3 is connected with the input end of the slow starting loop switch module 4 and used for controlling the slow starting loop switch module 4 to be opened or closed according to the switch control signal of the power supply system.

Specifically, the slow start current control module 3 controls the slow start loop switch module 4 to be turned on when the power supply system switch control signal is to turn on the power supply VCC of the power supply system, and controls the slow start loop switch module 4 to be turned off when the power supply system switch control signal is to turn off the power supply VCC of the power supply system.

In one embodiment, referring to fig. 2, the slow start current control module 3 includes a second signal amplifying unit, where the second signal amplifying unit includes a second amplifying element, a ninth resistor R9, and a tenth resistor R11.

Specifically, the second amplifying element may be an NPN transistor, an N-channel MOS transistor, or other types of amplifying elements, so long as the function of the second amplifying element can be implemented, and the specific type of the second amplifying element is not limited in this embodiment.

Optionally, the second amplifying element includes an NPN type triode Q4, one end of the ninth resistor R9 is connected with the power supply system switch control signal, the other end of the ninth resistor R9 is connected with the base of the NPN type triode Q4 and one end of the tenth resistor R11, an emitter of the NPN type triode Q4 and the other end of the tenth resistor R11 are grounded, and a collector of the NPN type triode Q4 is connected with an input end of the slow start loop switch module 4.

Specifically, when the power supply system switch control signal is a high level signal for controlling the power VCC of the power supply system to be turned on, the base of the NPN transistor Q4 is connected to a high level through the ninth resistor R9, so that the NPN transistor Q4 works in a conducting state, and the slow start loop switch module 4 is controlled to be turned on after the power supply system switch control signal is amplified, and the load circuit is pre-powered; when the power supply system switch control signal is a low level signal for controlling the power supply VCC of the power supply system to be turned off, the base electrode of the NPN transistor Q4 is connected to a low level through the ninth resistor R9, so that the NPN transistor Q4 works in a cut-off state, thereby controlling the slow start loop switch module 4 to be turned off rapidly and stopping pre-supplying power to the load circuit, so that the slow start loop can be turned off rapidly when the control signal for turning off the power supply VCC of the power supply system is received; when the power supply system switch control signal is absent, the base electrode of the NPN triode Q4 is grounded through the tenth resistor R11, so that the NPN triode Q4 is kept in a cut-off state, thereby controlling the slow start loop switch module 4 to remain closed, and no longer pre-supplying power to the load circuit. The ninth resistor R9 is a current limiting protection resistor.

The slow start loop switch module 4 comprises a constant current control unit and a slow start loop switch unit; the constant current control unit is respectively connected with a power supply VCC of the power supply system and the slow start loop switch unit, and the slow start loop switch unit is also respectively connected with the input end of the secondary voltage VCC_M feedback unit and the load circuit; the slow-start loop switch module 4 is configured to turn on or off a slow-start loop under the control of the slow-start current control module 3, and pre-supply power to the load circuit with a constant current when the slow-start loop is turned on, so that the main loop switch control module 2 controls the main loop switch module 1 to turn on when the secondary voltage vcc_m rises to the preset voltage threshold.

In one embodiment, referring to fig. 2, the slow start loop switch unit includes a third switch element, an eleventh resistor R6 and a twelfth resistor R4.

Specifically, the third switching element may be a P-channel MOS transistor or other types of switching elements, so long as the function of the third switching element can be implemented, and the specific type of the third switching element is not limited in this embodiment.

Optionally, the third switching element includes a second P-channel MOS transistor Q2; the constant current control unit comprises a third PNP triode Q3, a thirteenth resistor R2 and a fourteenth resistor R3; one end of the eleventh resistor R6 is connected with the collector of the NPN transistor Q4, the other end of the eleventh resistor R6 is connected with the collector of the third PNP transistor Q3, one end of the twelfth resistor R4 and the gate of the second P-channel MOS transistor Q2, the other end of the twelfth resistor R4 is connected with one end of the thirteenth resistor R2, one end of the fourteenth resistor R3 and the source of the second P-channel MOS transistor Q2, the drain of the second P-channel MOS transistor Q2 is connected with one end of the third resistor R7 and the load circuit, the other end of the thirteenth resistor R2 is connected with the power VCC of the power supply system and the emitter of the third PNP transistor Q3, and the other end of the fourteenth resistor R3 is connected with the base of the third PNP transistor Q3.

Specifically, when the NPN transistor Q4 is in the on state, a current flows from the power VCC of the power supply system through the thirteenth resistor R2, the twelfth resistor R4, and the eleventh resistor R6, so that the third PNP transistor Q3 is in the on state, the second P-channel MOS transistor Q2 is in the on state, and the power VCC of the power supply system supplies constant current to the load circuit through the thirteenth resistor R2 and the second P-channel MOS transistor Q2. When the current flowing through the thirteenth resistor R2 is too large, the voltage difference between the two ends of the resistor increases, so that the current flowing through the ground fourteen resistor increases, and further, the current flowing through the third PNP transistor Q3 increases, and the current flowing through the eleventh resistor R6 increases accordingly, so that the voltage difference between the two ends of the twelfth resistor R4 connected between the source and the gate of the second P-channel MOS transistor Q2 decreases, that is, the voltage between the source and the gate of the second P-channel MOS transistor Q2 decreases, and due to the miller platform effect of the P-channel MOS transistor, the on resistance in the second P-channel MOS transistor Q2 increases, and the current flowing through the thirteenth resistor R2 decreases, thereby playing a role in controlling the slow starting current. Therefore, the slow start current can be accurately and stably controlled. The adjustment of the magnitude of the slow starting current can be realized by adjusting the resistance values of the thirteenth resistor R2 and the fourteenth resistor R3 and/or the selection of the third PNP triode Q3, so that the slow starting current can be adjusted in a larger range, and more application scenes are met. The eleventh resistor R6 and the twelfth resistor R4 play a role of voltage division, so as to ensure that the second P-channel MOS transistor Q2 is safely turned on and off.

In an embodiment, referring to fig. 2, when the switch control signal of the power supply system is at a high level, the base of the NPN transistor Q4 is at a high level, so that the NPN transistor Q4 operates in a conducting state, and thus a current flows from the power source VCC of the power supply system through the thirteenth resistor R2, the twelfth resistor R4 and the eleventh resistor R6, so that the third PNP transistor Q3 operates in a conducting state, the second P-channel MOS transistor Q2 operates in a conducting state, and the power source VCC of the power supply system supplies constant current to the load circuit through the thirteenth resistor R2 and the second P-channel MOS transistor Q2;

when the switch control signal of the power supply system is at a high level, the base electrode of the first PNP transistor Q6 is at a high level, so that the first PNP transistor Q6 works in an off state, the second stage switch unit starts to work, the secondary voltage vcc_m is divided by the third resistor R7 and the sixth resistor R12, the capacitor C1 is charged through the sixth resistor R12, when the secondary voltage vcc_m reaches the preset voltage threshold, the capacitor C1 controls the reference voltage source U1 to output a low level signal to the base electrode of the second PNP transistor Q5 through the seventh resistor R10 after the charging is completed, so that the second PNP transistor Q5 works in an on state, so that current flows from the power supply of the power supply system through the first resistor R1 and the second resistor R5, the first P-channel MOS transistor Q1 works in an on state, and the power supply of the system is supplied to the load circuit VCC through the first P-channel MOS transistor Q1.

Specifically, by means of a simple and stable circuit design, when the switch control signal of the power supply system is a high level for controlling the power supply VCC of the power supply system to be turned on, the slow start circuit switch is closed firstly, constant current pre-supplies power to the load circuit, so that the secondary voltage VCC_M is higher and higher, and when the secondary voltage VCC_M reaches a preset voltage threshold value, the main circuit switch is closed, and at the moment, the power supply system is fully turned on to supply power to the load circuit; when the power supply system switch control signal is at a low level for controlling the power supply VCC of the power supply system to be closed, the main loop switch and the slow start switch are both closed rapidly.

The slow start circuit of the embodiment comprises a main loop switch module 1, a main loop switch control module 2, a slow start current control module 3 and a slow start loop switch module 4; when the switch control signal of the power supply system is at a high level for controlling the power supply VCC of the power supply system to be started, the slow start loop switch is closed firstly, and constant current is used for pre-supplying power to the load circuit, so that the secondary voltage VCC_M is higher and higher, when the secondary voltage VCC_M reaches a preset voltage threshold value, the main loop switch is closed, and at the moment, the power supply system is completely opened to supply power to the load circuit; when the power supply system switch control signal is at a low level for controlling the power supply VCC of the power supply system to be closed, the main loop switch and the slow start switch are both closed rapidly. Therefore, when the power supply system powers on a load, the load circuit is powered on in constant current through the slow start loop, and when the secondary voltage VCC_M reaches a preset voltage threshold value, the main loop switch is closed again, so that overcurrent protection of the power supply system caused by overlarge current at the moment of power on can be effectively prevented, and a switching device is ignited or a joint wire harness is damaged due to surge impact.

Example two

The present embodiment provides a power supply system, which includes the slow start circuit described in the first embodiment. When the power supply system is used for powering up a load, the load circuit is powered up in constant current through the slow start loop, and when the secondary voltage VCC_M reaches a preset voltage threshold value, the main loop switch is closed, so that overcurrent protection of the power supply system caused by overlarge current at the moment of powering up can be effectively prevented, and a switching device is ignited or a joint wire harness is damaged due to surge impact. The specific structure of the slow start circuit is as described in the first embodiment, and will not be described herein.

Example III

The present embodiment provides an electronic device, which includes the slow start circuit of the first embodiment. When the power supply system powers on a load, the electronic equipment of the embodiment supplies power to the load circuit in a constant current mode through the slow start loop, and when the secondary voltage VCC_M reaches a preset voltage threshold value, the main loop switch is closed, so that overcurrent protection of the power supply system caused by overlarge current at the moment of power on can be effectively prevented, and a switching device is ignited or a joint wire harness is damaged due to surge impact. The specific structure of the slow start circuit is as described in the first embodiment, and will not be described herein.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, article or apparatus that comprises the element.

The foregoing embodiment numbers of the present invention are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.

Claims

1. A slow start circuit for use in a power supply system, the slow start circuit comprising: the device comprises a main loop switch module, a main loop switch control module, a slow starting current control module and a slow starting loop switch module;

The slow start loop switch module comprises a constant current control unit and a slow start loop switch unit; the constant current control unit is respectively connected with a power supply of the power supply system and the slow start loop switch unit, and the slow start loop switch unit is also respectively connected with the input end of the secondary voltage feedback unit and the load circuit; the slow-start loop switch module is used for opening or closing a slow-start loop under the control of the slow-start current control module, and supplying power to the load circuit in advance by constant current when the slow-start loop is opened, so that the main loop switch control module controls the main loop switch module to be opened when the secondary voltage rises to the preset voltage threshold value;

wherein the main loop switch unit comprises a first switch element, a first resistor and a second resistor;

the first switching element comprises a first P-channel MOS tube, the source electrode of the first P-channel MOS tube is respectively connected with the power supply of the power supply system and one end of the first resistor, the grid electrode of the first P-channel MOS tube is respectively connected with the other end of the first resistor and one end of the second resistor, the drain electrode of the first P-channel MOS tube is respectively connected with the input end of the secondary voltage feedback unit and the load circuit, and the other end of the second resistor is connected with the output end of the main loop switch control module;

The secondary voltage feedback unit comprises a third resistor, one end of the third resistor is connected with the drain electrode of the first P-channel MOS tube and the load circuit respectively, and the other end of the third resistor is connected with the first input end of the main loop switch control module;

the main loop switch control module comprises a first-stage switch unit, a second-stage switch unit, a reference voltage source and a first signal amplifying unit; the first-stage switch unit is respectively connected with the power supply system switch control signal and the second-stage switch unit, the second-stage switch unit is also connected with the other end of the third resistor and the reference voltage source, the reference voltage source is also connected with the first signal amplifying unit, and the output end of the first signal amplifying unit is connected with the input control end of the main loop switch unit; the first-stage switch unit is used for controlling the second-stage switch unit to start working when the power supply system switch control signal is an on signal, and controlling the second-stage switch unit to stop working when the power supply system switch control signal is an off signal; and the second-stage switch unit is used for controlling the reference voltage source to output a low-level signal when the secondary voltage reaches a preset voltage threshold value so as to control the first signal amplifying unit to start working and further control the main loop switch module to start the power supply of the power supply system to supply power for the load circuit.

2. The slow start circuit according to claim 1, wherein the first stage switching unit comprises a second switching element, a fourth resistor and a fifth resistor, the second switching element comprises a first PNP type triode, one end of the fourth resistor is connected with the power supply system switch control signal, the other end of the fourth resistor is respectively connected with one end of the fifth resistor and a base electrode of the first PNP type triode, the other end of the fifth resistor and a collector electrode of the first PNP type triode are grounded, and an emitter electrode of the first PNP type triode is respectively connected with the other end of the third resistor and the second stage switching unit;

3. The slow start circuit according to claim 2, wherein the slow start current control module comprises a second signal amplifying unit, the second signal amplifying unit comprises a second amplifying element, a ninth resistor and a tenth resistor, the second amplifying element comprises an NPN-type triode, one end of the ninth resistor is connected with the power supply system switch control signal, the other end of the ninth resistor is connected with a base electrode of the NPN-type triode and one end of the tenth resistor respectively, an emitter electrode of the NPN-type triode and the other end of the tenth resistor are grounded, and a collector electrode of the NPN-type triode is connected with an input end of the slow start loop switch module.

4. The slow start circuit of claim 3, wherein the slow start loop switching unit comprises a third switching element, an eleventh resistor and a twelfth resistor, the third switching element comprising a second P-channel MOS transistor; the constant current control unit comprises a third PNP triode, a thirteenth resistor and a fourteenth resistor; one end of the eleventh resistor is connected with the collector of the NPN triode, the other end of the eleventh resistor is respectively connected with the collector of the third PNP triode, one end of the twelfth resistor and the grid electrode of the second P channel MOS tube, the other end of the twelfth resistor is respectively connected with one end of the thirteenth resistor, one end of the fourteenth resistor and the source electrode of the second P channel MOS tube, the drain electrode of the second P channel MOS tube is respectively connected with one end of the third resistor and the load circuit, the other end of the thirteenth resistor is respectively connected with the power supply of the power supply system and the emitter of the third PNP triode, and the other end of the fourteenth resistor is connected with the base electrode of the third PNP triode.

5. The slow start circuit according to claim 4, wherein when the power supply system switch control signal is at a high level, a base electrode of the NPN transistor is at a high level, so that the NPN transistor is operated in a conducting state, and thus a current flows from a power supply of the power supply system through the thirteenth resistor, the twelfth resistor and the eleventh resistor, so that the three PNP transistor is operated in the conducting state, the second P-channel MOS transistor is operated in the conducting state, and the power supply of the power supply system supplies constant current to the load circuit through the thirteenth resistor and the second P-channel MOS transistor;

6. A power supply system, characterized in that the power supply system comprises a soft start circuit as claimed in any one of claims 1-5.

7. An electronic device comprising a soft start circuit as claimed in any one of claims 1 to 5.