CN114189139A

CN114189139A - Slow starting circuit, power supply system and electronic equipment

Info

Publication number: CN114189139A
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: 2022-03-15
Anticipated expiration: 2041-12-02
Also published as: CN114189139B

Abstract

The invention discloses a slow starting circuit, a power supply system and electronic equipment, and belongs to the technical field of electronic equipment. This slow start circuit includes: the device comprises 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 started, the slow start loop switch is closed first, and the load circuit is pre-supplied with power by the constant current, 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 opened to supply power to the load circuit; when the switch control signal of the power supply system is at a low level for controlling the power supply of the power supply system to be turned off, the main circuit switch and the slow starting switch are both rapidly turned off. Therefore, overcurrent protection of a power supply system caused by overlarge current at the moment of electrification can be effectively prevented, and a switch device is ignited or a connector wire harness is damaged due to surge impact.

Description

Slow starting 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 a power supply system of the electronic equipment directly powers on the load circuit, overcurrent protection of the power supply system can be caused, and a switching device is ignited or a connector wire harness is damaged due to surge impact. A slow start circuit solution is needed.

Disclosure of Invention

In view of the above, an embodiment of the present invention provides a slow start circuit, a power supply system and an electronic device, so as to solve the technical problems that in the 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, overcurrent protection of the power supply system may be caused, and a switch device is ignited or a connector wiring 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 the embodiments 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 start current control module and a slow start loop switch module;

the main loop switch module comprises a main loop switch unit and a secondary voltage feedback unit; the power supply input end of the main loop switch unit is connected with a power supply of a power supply system, the power supply 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 used for turning on or turning off 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 back secondary voltage 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 value 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 value;

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

the slow starting loop switch module comprises a constant current control unit and a slow starting 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 the slow start loop under the control of the slow start current control module, and pre-supplies power to the load circuit at a 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 circuit 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, a source electrode of the first P-channel MOS tube is respectively connected with a power supply of the power supply system and one end of the first resistor, a 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, a drain electrode of the first P-channel MOS tube is respectively connected with an input end of the secondary voltage feedback unit and the load circuit, and the other end of the second resistor is connected with an 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 to the drain of the first P-channel MOS transistor and the load circuit, and the other end of the third resistor is connected to the first input end of the main loop switch control module.

Optionally, the main loop switch control module includes a first stage switch unit, a second stage switch unit, a reference voltage source, and a first signal amplification 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 amplification unit, and the output end of the first signal amplification 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 amplification unit to start working, and further controlling the main loop switch module to start a power supply of the power supply system to supply power to the load circuit.

Optionally, the first stage switching unit includes a second switching element, a fourth resistor, and a fifth resistor, the second switching element includes a first PNP type triode, one end of the fourth resistor is connected to the power supply system switch control signal, the other end of the fourth resistor is connected to one end of the fifth resistor and the base of the first PNP type triode, respectively, 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 to 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, 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 amplification unit, and the grounding end of the reference voltage source is grounded;

the first signal amplification unit comprises a first amplification element, a seventh resistor and an eighth resistor, the first amplification 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 connected with one end of the eighth resistor and the base electrode of the second PNP type triode respectively, the other end of the eighth resistor is connected with the other end of the second resistor and the emitting electrode of the second PNP type triode respectively, and the collecting electrode of the second PNP type triode is grounded.

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

Optionally, the soft 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 type triode, a thirteenth resistor and a fourteenth resistor; one end of the eleventh resistor is connected with a collector of the NPN-type triode, the other end of the eleventh resistor is connected with a collector of the third PNP-type triode, one end of the twelfth resistor and a gate of the second P-channel MOS transistor respectively, the other end of the twelfth resistor is connected with one end of the thirteenth resistor, one end of the fourteenth resistor and a source of the second P-channel MOS transistor respectively, a drain of the second P-channel MOS transistor is connected with one end of the third resistor and the load circuit respectively, the other end of the thirteenth resistor is connected with a power supply of the power supply system and an emitter of the third PNP-type triode respectively, and the other end of the fourteenth resistor is connected with a base of the third PNP-type triode.

Optionally, when the power supply system switch control signal is at a high level, the base of the NPN type triode is at a high level, so that the NPN type triode operates in a conducting state, and thus a 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 type triode operates in a conducting state, the second P-channel MOS transistor operates in a conducting state, and the power supply of the power supply system pre-supplies power to the load circuit by a constant current through the thirteenth resistor and the second P-channel MOS transistor;

when the power supply system switch control signal is at high level, the base electrode of the first PNP type triode is at high level, 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 the capacitor is charged 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 charging is finished, so that the second PNP type triode works in a conducting state, so that current flows from the power supply of the power supply system through the first resistor and the second resistor, the first P-channel MOS tube works in a conducting state, and a 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 embodiments of the present invention, there is provided a power supply system including the above-mentioned slow start circuit.

According to another aspect of the embodiments of the present invention, there is provided an electronic device including the slow 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 started, the slow start loop switch is closed first, and the load circuit is pre-supplied with power by the constant current, 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 opened to supply power to the load circuit; when the switch control signal of the power supply system is at a low level for controlling the power supply of the power supply system to be turned off, the main circuit switch and the slow starting switch are both rapidly turned off. Therefore, when the power supply system powers a load, constant-current pre-power supply is firstly performed on the load circuit through the slow start loop, and when the secondary voltage 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 supply can be effectively prevented, and a switch device is ignited or a connector 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 diagram of an embodiment of a slow start circuit according to the present invention;

fig. 2 is a circuit connection diagram of an embodiment of a slow start circuit according to the present invention.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the following description, suffixes such as "module", "element", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no specific meaning in itself. Thus, "module", "element" or "unit" may be used mixedly.

Example one

In order to solve the technical problems that in the conventional electronic device, because the capacitance of the load circuit is large, if the power supply system of the electronic device directly powers on the load circuit, overcurrent protection of the power supply system may be caused, a switching device is ignited, or a connector harness is damaged due to surge impact, the present embodiment provides a slow start circuit, please refer to fig. 1, where fig. 1 is a schematic diagram of an embodiment of the slow start circuit provided in the embodiment of the present invention. The slow starting circuit comprises a main loop switch module 1, a main loop switch control module 2, a slow starting current control module 3 and a slow starting 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 supply input end of the main loop switch unit is connected with a power supply VCC of a power supply system, the power supply output end of the main loop switch unit is respectively connected with the input end of the secondary voltage VCC _ M feedback unit and a 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 used for turning on or turning off the power supply 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 back the secondary voltage VCC _ M to the main loop switch control module 2.

Specifically, the load circuit is not shown in fig. 1, and a specific circuit structure of the load circuit may vary according to an electronic device to which the soft start circuit is applied. The main loop switch module 1 is used for turning on or turning off the power supply VCC of the power supply system under the control of the main loop switch control module 2, and feeding back the secondary voltage VCC _ M to the main loop switch control module 2 through the secondary voltage VCC _ M feedback unit, so that the main loop switch control module 2 controls the turning on and turning off of the main loop switch module 1 according to the secondary voltage VCC _ M.

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

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

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

Specifically, the load circuit is not shown in fig. 2, and a specific circuit structure of the load circuit may vary according to an electronic device to which the soft start circuit is applied. The first P-channel MOS transistor Q1 realizes the on and off actions of the power supply VCC of the power supply system. Optionally, the first P-channel MOS transistor Q1 employs a P-channel MOS transistor with low internal resistance, so as to reduce power consumption of the main circuit switching unit. The first resistor R1 and the second resistor R5 divide the voltage of the power source VCC of the power supply system, thereby ensuring that the first P-channel MOS transistor Q1 is safely turned on or off.

In one 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, respectively, 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 circuit switch control module 2, so that the main circuit switch control module 2 controls the main circuit switch module 1 to be turned on and off 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 opened under the control of the power supply system switch control signal when the secondary voltage VCC _ M reaches a preset voltage threshold value, and controlling the main loop switch module 1 to be closed when the secondary voltage VCC _ M does not reach the preset voltage threshold value.

Specifically, 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 the 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 value, the main loop switch module 1 is controlled to be opened, and when the secondary voltage VCC _ M does not reach the preset voltage threshold value, the main loop switch module 1 is controlled to be closed.

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 power supply system switch control signal and the second-stage switch unit, the second-stage switch unit is further connected with the other end of the third resistor R7 and the reference voltage source U1, the reference voltage source U1 is further connected with the first signal amplification unit, and the output end of the first signal amplification 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 U1 to output a low level signal when the secondary voltage VCC _ M reaches a preset voltage threshold value so as to control the first signal amplification unit to start working, so as to further control the main loop switch module 1 to start the power supply VCC of the power supply system, and supply power to the load circuit.

Specifically, the first-stage switch unit is further configured to control the second-stage switch unit to remain in an inoperative state when the power supply system switch control signal is missing. When the second stage switch unit does not work, the reference voltage source U1 outputs a high level signal to control the first signal amplification unit to also work, so as to further control the main loop switch module 1 to keep the off state of the power supply VCC of the power supply system, and not supply power to the load circuit.

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

Specifically, the second switch element may adopt a PNP triode, a P-channel MOS transistor, or another type of switch element as long as the function of the second switch element can be realized, and the specific type of the second switch element is not limited in this embodiment.

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

Specifically, 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 of the first PNP type triode Q6 is connected to a low level through the fourth resistor R13, so that the first PNP type triode Q6 operates in a conducting state, and the other end of the third resistor R7 is connected to ground through the first PNP type triode Q6, thereby controlling the second stage switch unit to stop operating; 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 of the first PNP type triode Q6 is connected to a high level through the fourth resistor R13, so that the first PNP type triode Q6 operates in a cut-off state, and the other end of the third resistor R7 is disconnected from the ground, thereby controlling the second stage switch unit to start operating; when the power supply system switch control signal is absent, the base of the first PNP transistor Q6 is grounded through the fifth resistor R14, so that the first PNP transistor Q6 operates in a conducting state, and the other end of the third resistor R7 is connected to ground through the first PNP transistor Q6, thereby controlling the second stage switch unit to be kept in a non-operating 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 transistor Q6, and therefore, the second stage switching unit composed of the sixth resistor R12 and the capacitor C1 stops operating when the first PNP transistor Q6 is turned on, and starts operating when the first PNP transistor Q6 is turned off. When the second level switch unit begins to work, secondary voltage VCC _ M warp third resistance R7 and sixth resistance R12 partial pressure back, pass through sixth resistance R12 give electric capacity C1 charges, works as secondary voltage VCC _ M reaches preset voltage threshold just electric capacity C1 charges when accomplishing, control reference voltage source U1 output low level signal, in order to control first signal amplification unit begins to work, in order to further control main loop switch module 1 opens power supply system's power VCC, for load circuit supplies power. When the second-stage switch unit stops working, the secondary voltage VCC _ M fed back by the third resistor R7 passes through the first PNP type triode Q6 and is grounded, so that the reference voltage source U1 outputs a high level signal to control the first signal amplification unit to stop working, so as to further control the main loop switch module 1 to close the power supply VCC of the power supply system and stop supplying power to the load circuit. Through adjusting the resistance of third resistance R7 and sixth resistance R12, can realize right the regulation of main loop switch unit's opening voltage to secondary voltage VCC _ M value after can setting up slowly and starting in a flexible way avoids switching device's the phenomenon of striking sparks. The capacitor C1 can realize the delayed opening and delayed closing of the main loop switch unit.

The voltage output end of the reference voltage source U1 is connected with the first signal amplification 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 amplification unit according to the control of the second stage switch unit. The feedback is accurately made and the main loop switch module 1 is opened when the switch control signal of the power supply system is at a high level and the secondary voltage VCC _ M reaches a preset voltage threshold.

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

Optionally, the first amplifying element includes a second PNP transistor 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 transistor 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 transistor Q5, and the collector of the second PNP transistor Q5 is grounded.

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

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

Specifically, the slow start current control module 3 is in the power supply system switch control signal is for opening during power supply system's power VCC, control the slow start loop switch module 4 opens power supply system switch control signal is for closing during power supply system's power VCC, control the slow start loop switch module 4 closes.

In one embodiment, referring to fig. 2, the slow start current control module 3 includes a second signal amplifying unit, and 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 adopt an NPN type triode, an N-channel MOS transistor, or other type of amplifying element as long as the function of the second amplifying element can be realized, and the specific type of the second amplifying element is not limited in this embodiment.

Optionally, the second amplifying element includes an NPN transistor Q4, one end of the ninth resistor R9 is connected to the power supply system switch control signal, the other end of the ninth resistor R9 is connected to the base of the NPN transistor Q4 and one end of the tenth resistor R11, respectively, the emitter of the NPN transistor Q4 and the other end of the tenth resistor R11 are grounded, and the collector of the NPN transistor Q4 is connected to the input of the soft start circuit switch module 4.

Specifically, 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 of the NPN type triode Q4 is connected to a high level through the ninth resistor R9, so that the NPN type triode Q4 operates in a conducting state, and the NPN type triode Q4 controls the slow start circuit switch module 4 to be turned on after the power supply system switch control signal is amplified, and starts to pre-supply power to the load circuit; 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 of the NPN type triode Q4 is connected to a low level through the ninth resistor R9, so that the NPN type triode Q4 operates in a cut-off state, thereby controlling the slow start loop switch module 4 to be turned off rapidly, stopping supplying power to the load circuit in advance, and thus being capable of closing the slow start loop rapidly when receiving the control signal for turning off the power supply VCC of the power supply system; when the power supply system switch control signal is absent, the base of the NPN type triode Q4 is grounded through the tenth resistor R11, so that the NPN type triode Q4 is kept in a cut-off state, and the slow start loop switch module 4 is controlled to be kept closed, and no power is supplied to the load circuit any more. The ninth resistor R9 is a current-limiting protection resistor.

The slow starting loop switch module 4 comprises a constant current control unit and a slow starting 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 open or close the slow start loop under the control of the slow start current control module 3, and pre-supply power to the load circuit at a constant current when the slow start loop is opened, so that the main loop switch control module 2 controls the main loop switch module 1 to be opened when the secondary voltage VCC _ M rises to the preset voltage threshold.

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

Specifically, the third switching element may adopt a P-channel MOS transistor or another type of switching element as long as the function of the third switching element can be realized, 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 type triode Q3, a thirteenth resistor R2 and a fourteenth resistor R3; one end of the eleventh resistor R6 is connected to a collector of the NPN transistor Q4, the other end of the eleventh resistor R6 is connected to a collector of the third PNP transistor Q3, one end of the twelfth resistor R4 and a gate of the second P-channel MOS Q2, the other end of the twelfth resistor R4 is connected to one end of the thirteenth resistor R2, one end of the fourteenth resistor R3 and a source of the second P-channel MOS Q2, a drain of the second P-channel MOS Q2 is connected to one end of the third resistor R7 and the load circuit, the other end of the thirteenth resistor R2 is connected to the power source VCC of the power supply system and an emitter of the third PNP transistor Q3, and the other end of the fourteenth resistor R3 is connected to a base of the third PNP transistor Q3.

Specifically, when the NPN transistor Q4 operates in the on state, 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 the on state, the second P-channel MOS transistor Q2 operates in the on state, and the power source VCC of the power supply system pre-supplies the 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 fourteenth resistor increases, and further the current flowing through the third PNP transistor Q3 increases, and the current flowing through the eleventh resistor R6 also increases, thereby causing 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 to decrease, that is, the voltage between the source and the gate of the second P-channel MOS transistor Q2 to decrease, and due to the miller plateau action of the P-channel MOS transistor, the internal on-resistance of the second P-channel MOS transistor Q2 increases, so that the current flowing through the thirteenth resistor R2 decreases, and thus the slow start current control function can be achieved. Therefore, the slow starting current can be accurately and stably controlled. The magnitude of the slow starting current can be adjusted by adjusting the resistance values of the thirteenth resistor R2 and the fourteenth resistor R3 and/or the type selection of the third PNP triode Q3, so that the slow starting current can be adjusted in a large range, and more application scenes are met. The eleventh resistor R6 and the twelfth resistor R4 perform a voltage dividing function, thereby ensuring that the second P-channel MOS transistor Q2 is safely turned on and off.

In one embodiment, referring to fig. 2, when the power supply system switch control signal 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 supply 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 Q2 operates in a conducting state, and the power supply VCC of the power supply system pre-supplies a constant current to the load circuit through the thirteenth resistor R2 and the second P-channel MOS Q2;

when the power supply system switch control signal is at a high level, the base of the first PNP transistor Q6 is at a high level, so that the first PNP transistor Q6 operates in an off state, the second-stage switch unit starts to operate, 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 of the second PNP transistor Q5 through the seventh resistor R10 after charging is completed, so that the second PNP transistor Q5 operates in an on state, and thus, current flows from the power supply VCC of the power supply system through the first resistor R1 and the second resistor R5, so that the first P-channel MOS transistor Q1 operates in an on state, and a power supply VCC of the power supply system supplies power to the load circuit through the first P-channel MOS tube Q1.

Specifically, the slow start circuit of the embodiment implements that, through a simple and stable circuit design, when a switch control signal of a power supply system is at a high level for controlling the power supply VCC of the power supply system to be turned on, a slow start circuit switch is firstly closed, and a load circuit is pre-supplied with a constant current, so that the secondary voltage VCC _ M becomes higher and higher, and when the secondary voltage VCC _ M reaches a preset voltage threshold, a main circuit switch is closed, and at this time, the power supply system is completely turned on to supply power to the load circuit; when the switch control signal of the power supply system is at a low level for controlling the power supply VCC of the power supply system to be switched off, the main loop switch and the slow start switch are both rapidly switched off.

The slow start circuit of the embodiment includes 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 a power supply system switch control signal is at a high level for controlling the power supply VCC of a power supply system to be switched on, firstly, closing a slow start loop switch, and pre-supplying power to a load circuit by a constant current, so that the secondary voltage VCC _ M is higher and higher, and when the secondary voltage VCC _ M reaches a preset voltage threshold, closing a main loop switch, and at the moment, completely switching on the power supply system to supply power to the load circuit; when the switch control signal of the power supply system is at a low level for controlling the power supply VCC of the power supply system to be switched off, the main loop switch and the slow start switch are both rapidly switched off. Therefore, when the power supply system powers a load, constant-current pre-power supply is firstly performed on the load circuit 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 supply can be effectively prevented, and a switch device is ignited or a connector 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 powers a load, the power supply system firstly supplies power to the load circuit in a constant-current pre-supplying mode through the slow start loop, and then closes the main loop switch when the secondary voltage VCC _ M reaches a preset voltage threshold value, so that overcurrent protection of the power supply system caused by overlarge current at the moment of power supply can be effectively prevented, and a switch device is ignited or a connector wire harness is damaged due to surge impact. The specific structure of the slow start circuit is as described in the above embodiment, and is not described herein again.

EXAMPLE III

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

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 an … …" does not exclude the presence of other like elements in a process, article, or apparatus that comprises the element.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A slow start circuit, applied to 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 start current control module and a slow start loop switch module;

2. The slow start circuit according to claim 1, wherein the main loop switching unit includes a first switching element, a first resistor, and a second resistor;

3. The slow start circuit as claimed in claim 2, wherein the secondary voltage feedback unit comprises a third resistor, one end of the third resistor is connected to the drain of the first P-channel MOS transistor and the load circuit, and the other end of the third resistor is connected to the first input terminal of the main loop switch control module.

4. The slow start circuit according to claim 3, wherein 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 amplification unit, and the output end of the first signal amplification 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 amplification unit to start working, and further controlling the main loop switch module to start a power supply of the power supply system to supply power to the load circuit.

5. The slow start circuit according to claim 4, wherein the first stage switching unit includes a second switching element, a fourth resistor and a fifth resistor, the second switching element includes a first PNP type triode, one end of the fourth resistor is connected to the power supply system switching control signal, the other end of the fourth resistor is connected to one end of the fifth resistor and the base of the first PNP type triode, respectively, 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 to the other end of the third resistor and the second stage switching unit, respectively;

6. The slow start circuit according to claim 5, wherein 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 to the power supply system switch control signal, the other end of the ninth resistor is connected to a base of the NPN type triode and one end of the tenth resistor, respectively, an emitter of the NPN type triode and the other end of the tenth resistor are grounded, and a collector of the NPN type triode is connected to the input end of the slow start circuit switch module.

7. The slow start circuit according to claim 6, wherein the slow start loop switch unit comprises a third switch element, an eleventh resistor and a twelfth resistor, the third switch element comprises a second P-channel MOS transistor; the constant current control unit comprises a third PNP type triode, a thirteenth resistor and a fourteenth resistor; one end of the eleventh resistor is connected with a collector of the NPN-type triode, the other end of the eleventh resistor is connected with a collector of the third PNP-type triode, one end of the twelfth resistor and a gate of the second P-channel MOS transistor respectively, the other end of the twelfth resistor is connected with one end of the thirteenth resistor, one end of the fourteenth resistor and a source of the second P-channel MOS transistor respectively, a drain of the second P-channel MOS transistor is connected with one end of the third resistor and the load circuit respectively, the other end of the thirteenth resistor is connected with a power supply of the power supply system and an emitter of the third PNP-type triode respectively, and the other end of the fourteenth resistor is connected with a base of the third PNP-type triode.

8. The slow start circuit according to claim 7, wherein when the power supply system switch control signal is at a high level, the base of the NPN type transistor is at a high level, so that the NPN type transistor operates in a conducting state, and thus a current flows from the power supply system to the thirteenth resistor, the twelfth resistor, and the eleventh resistor, so that the three PNP type transistors operate in a conducting state, and the second P-channel MOS transistor operates in a conducting state, and the power supply system supplies the constant current pre-power to the load circuit through the thirteenth resistor and the second P-channel MOS transistor;

9. A power supply system, characterized in that it comprises a slow start circuit according to any one of claims 1-8.

10. An electronic device, characterized in that the electronic device comprises a soft start circuit as claimed in any one of claims 1-8.