CN115776227A - Drive circuit and DC-DC power supply system - Google Patents

Abstract

The present invention provides a driving circuit, including: the control module is used for carrying out resistance voltage division on the first power supply voltage to generate a control voltage; the first control end of the driving module is connected with the output end of the control module, the second control end of the driving module is connected with the PWM signal through a first resistor, the input end of the driving module is connected with a second power supply voltage, and the output end of the driving module is connected with the grid electrode of the power tube through a second resistor; the power tube is used for generating a driving voltage based on a second power supply voltage to drive the power tube when the PWM signal is at a low level; the first control end of the reset module is connected with the output end of the control module, the second control end of the reset module is connected with the PWM signal through a first resistor, the input end of the reset module is connected with the grid electrode of the power tube through a second resistor, and the output end of the reset module is grounded; and the power tube is used for discharging and resetting the power tube when the PWM signal is at a high level. The driving circuit provided by the invention solves the problem that the driving voltage of the existing driving circuit is difficult to improve due to overlarge voltage drop between the base electrode and the emitting electrode of the triode.

Description

Drive circuit and DC-DC power supply system

Technical Field

The invention belongs to the field of integrated circuit design, and particularly relates to a driving circuit and a DC-DC power supply system.

Background

With the advent of the 5G era, scientific and technical development is changing day by day, and the demand for power supplies is becoming more and more important due to the diversification of products, and more power supply application demands are also being brought up to date. With the development of product technologies such as communication servers, mobile phones, computers, air conditioners, TVs and the like, the functions of the main control chip are more and more powerful, and meanwhile, the power consumption of the main control chip is increased increasingly. At present, the main control chip of such products generally adopts 5V, 3.3V or 1.1V power supply, and the power supply current also rises from several amperes to dozens of amperes or even hundreds of amperes.

It is known that the larger the current is, the more difficult the design of the power supply is, and the large current causes the power supply to have serious loss and heat generation, which also presents a strong challenge to our power device. A power semiconductor MOSFET (metal-oxide-semiconductor field effect transistor) is one of important power devices of a power supply product, and in some dc conversion power supply systems for supplying power to a main control chip of the product, a MOSFET with a lower driving voltage is generally selected, for example, a MOSFET with a gate voltage of about 4.5V is selected, so as to reduce driving loss and meet the application of low-voltage driving.

Because the input voltage is low, especially for 5V or 3.3V power supply, generally DC-DC (direct current-direct current) conversion is required, and most of MOSFET driving power supply adopts the power input end to get power, but because the power supply voltage is too low, it is difficult to meet the driving voltage requirement of MOSFET.

The existing driving circuit adopts a direct driving mode of an IC chip (as shown in figure 1), and has the advantages of simplicity, reliability and low cost; the defects are obvious, the driving capability is very limited by completely depending on the IC chip, and the driving speed and the discharge speed of the MOSFET both depend on the driving capability of the IC chip.

Another conventional driving circuit adopts a totem pole driving method (as shown in fig. 2), when the PWM signal is at a high level (e.g., 5V), the transistor Q1 is turned on, at this time, the emitter of the transistor Q1 outputs a voltage of 4.3V, which is determined by the characteristics of the transistor, and the driving current is provided by the power supply terminal VCC. The driving method has the advantages that the driving current can be enhanced, and the driving capability is enhanced; however, the driving voltage cannot be increased, and due to the 0.7V voltage drop between the base and the emitter of the triode Q1, the driving voltage of 5V is greatly reduced due to the large voltage drop, so that the driving voltage of the triode Q1 is possibly insufficient and cannot be completely turned on, the triode Q1 works in an amplification area, and when the collector-emitter current flowing through the triode Q1 is too large, the temperature rise of the triode Q1 is directly too high, and in a serious situation, the device is even burnt and damaged.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a driving circuit and a DC-DC power supply system, which are used to solve the problem that the driving voltage of the conventional driving circuit is difficult to increase due to the excessive voltage drop between the base and the emitter of the transistor.

To achieve the above and other related objects, the present invention provides a driving circuit, including:

the control module is used for carrying out resistance voltage division on the first power supply voltage to generate a control voltage;

the first control end of the driving module is connected with the output end of the control module, the second control end of the driving module is connected with the PWM signal through a first resistor, the input end of the driving module is connected with a second power supply voltage, and the output end of the driving module is connected with the grid electrode of the power tube through a second resistor; the power tube is used for generating a driving voltage based on the second power supply voltage to drive the power tube when the PWM signal is at a low level, wherein the driving voltage is equal to the difference value between the second power supply voltage and the voltage drop between the emitter and the collector of the triode;

the first control end of the reset module is connected with the output end of the control module, the second control end of the reset module is connected with the PWM signal through a first resistor, the input end of the reset module is connected with the grid electrode of the power tube through a second resistor, and the output end of the reset module is grounded; and the power tube is used for discharging and resetting when the PWM signal is at a high level.

Optionally, the driving module comprises: the base electrode of the first NPN type triode is connected with the output end of the control module, the emitting electrode of the first NPN type triode is connected with the PWM signal through the first resistor, the collecting electrode of the first NPN type triode is connected with the base electrode of the first PNP type triode, the emitting electrode of the first PNP type triode is connected with the second power voltage through the third resistor, and the collecting electrode of the first PNP type triode is connected with the grid electrode of the power tube through the second resistor.

Optionally, the driving module further comprises: and the first filter capacitor is connected between the second power supply voltage and the ground.

Optionally, the reset module includes: the base electrode of the second PNP type triode is connected with the output end of the control module, the emitting electrode of the second PNP type triode is connected with the PWM signal through the first resistor, the collecting electrode of the second PNP type triode is connected with the base electrode of the second NPN type triode, the emitting electrode of the second NPN type triode is grounded, the collecting electrode of the second NPN type triode is connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the grid electrode of the power tube through the second resistor.

Optionally, the reset module further comprises: the second filter capacitor and the fifth resistor are connected between the base of the second NPN type triode and the ground in parallel.

Optionally, the control module comprises: one end of the sixth resistor is connected with the first power supply voltage, the other end of the sixth resistor is connected with one end of the seventh resistor and serves as the output end of the control module, and the other end of the seventh resistor is grounded.

Optionally, the control module further comprises: one end of the eighth resistor is connected with the first power supply voltage, and the other end of the eighth resistor is connected with one end of the sixth resistor; at this time, the driving circuit further includes: and the anode of the diode is connected with the second power supply voltage, and the cathode of the diode is connected with the other end of the eighth resistor.

Optionally, the driving circuit further comprises: and the negative feedback module is connected between the grid of the power tube and the first control end of the driving module and is used for performing negative feedback control on the second power supply voltage by adjusting the control voltage when the second power supply voltage fluctuates.

Optionally, the negative feedback module includes: the power supply comprises a third NPN type triode, a ninth resistor and a tenth resistor, wherein one end of the ninth resistor is connected with the grid electrode of the power tube, the other end of the ninth resistor is connected with one end of the tenth resistor and the base electrode of the third NPN type triode, the other end of the tenth resistor is grounded, the emitting electrode of the third NPN type triode is grounded, and the collecting electrode of the third NPN type triode is connected with the first control end of the driving module.

Optionally, the negative feedback module includes: and the third filter capacitor is connected between the base of the third NPN type triode and the ground.

The present invention also provides a DC-DC power supply system, including: a drive circuit as claimed in any one of the preceding claims.

As described above, according to the driving circuit and the DC-DC power supply system of the present invention, through the design of the control module, the driving module and the reset module, a brand new MOSFET driving circuit is provided, which has the advantages of strong driving capability, small driving voltage drop, adjustable driving voltage and driving current, and can be applied to MOSFET driving application of low-voltage power supply products, and also can drive a high-power MOSFET and meet the requirement of driving voltage amplitude; in addition, the driving circuit has a negative feedback regulation function, can effectively limit the fluctuation of the grid voltage peak value of the MOSFET and ensures the stability of the grid voltage.

Drawings

Fig. 1 is a circuit diagram of a conventional driving circuit.

Fig. 2 is a circuit diagram of another conventional driving circuit.

Fig. 3 is a circuit diagram of the driving circuit according to an embodiment of the invention.

Fig. 4 is a circuit diagram of a driving circuit according to a second embodiment of the invention.

Fig. 5 is a circuit diagram of a DC-DC power supply system according to a third embodiment of the invention.

Fig. 6 is a schematic circuit diagram of a control chip according to a third embodiment of the present invention.

Description of the element reference numerals

100. Driving circuit

101. Control module

102. Drive module

103. Reset module

104. Negative feedback module

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 3 to 6. It should be noted that the drawings provided in the present embodiment are only for schematically illustrating the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.

Example one

As shown in fig. 3, the present embodiment provides a driving circuit, where the driving circuit 100 includes:

the control module 101 is configured to perform resistance voltage division on the first power supply voltage LVCC to generate a control voltage;

a driving module 102, a first control end of which is connected to the output end of the control module 101, a second control end of which is connected to the PWM signal through a first resistor R1, an input end of which is connected to a second power voltage HVCC, and an output end of which is connected to the gate of the power tube MOSFET through a second resistor R2; the power tube MOSFET is used for generating a driving voltage based on the second power supply voltage HVCC to drive the power tube MOSFET when the PWM signal is at a low level, wherein the driving voltage is equal to the difference value of the second power supply voltage HVCC and the voltage drop between an emitter and a collector of a triode;

the reset module 103 is provided with a first control end connected with the output end of the control module 101, a second control end connected with a PWM signal through a first resistor R1, an input end connected with the grid electrode of the power tube MOSFET through a second resistor R2, and an output end grounded; and the power tube MOSFET is used for discharging and resetting when the PWM signal is at a high level.

It should be noted that the voltage values of the first power voltage LVCC and the second power voltage HVCC may be the same or different, which has no influence on this embodiment.

Specifically, as shown in fig. 3, the control module 101 includes: one end of the sixth resistor R6 is connected to the first power supply voltage LVCC, the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and serves as an output end of the control module 101, and the other end of the seventh resistor R7 is grounded.

In this embodiment, by adjusting the resistance values of the sixth resistor R6 and the seventh resistor R7, a suitable control voltage (generally greater than 1V) can be generated at the point B, so as to ensure that the first NPN transistor Q1 can be normally turned on when the PWM signal is at a low level.

Specifically, as shown in fig. 3, the driving module 102 includes: the base electrode of the first NPN type triode Q1 is connected to the output end of the control module 101, the emitting electrode of the first NPN type triode Q1 is connected to the PWM signal through the first resistor R1, the collector electrode of the first NPN type triode Q1 is connected to the base electrode of the first PNP type triode Q2, the emitting electrode of the first PNP type triode Q2 is connected to the second power supply voltage HVCC through the third resistor R3, and the collector electrode of the first PNP type triode Q2 is connected to the gate electrode of the power tube MOSFET through the second resistor R2.

In this embodiment, when the PWM signal is at a low level (that is, the point a is at a low level), the control voltage at the point B is sufficient to turn on the first NPN type triode Q1, pull the base of the first PNP type triode Q2 to a low level, and turn on the first PNP type triode Q2; at this time, the second power supply voltage HVCC directly drives the power transistor MOSFET through the emitter-collector of the first PNP transistor Q2, and since the voltage drop between the emitter and the collector of the first PNP transistor Q2 is only 0.3V, a driving voltage of (HVCC-0.3V) can be obtained at point C, and if HVCC is 5V, the driving voltage is 5V-0.3V =4.7v, which is 0.4V higher than the existing driving voltage, and is sufficient to ensure that the power transistor MOSFET with a gate voltage of 4.5V is fully opened. In addition, the second resistor R2 and the third resistor R3 are current-limiting resistors, and the magnitude of the driving current can be set by adjusting the resistance values of the second resistor R2 and the third resistor R3.

More specifically, as shown in fig. 3, the driving module 102 further includes: and the first filtering capacitor C1 is connected between the second power supply voltage HVCC and the ground and used for filtering the second power supply voltage HVCC to filter out noise waves therein and ensure the stability of the second power supply voltage HVCC.

Specifically, as shown in fig. 3, the reset module 103 includes: the base of the second PNP triode Q3 is connected to the output end of the control module 101, the emitter of the second PNP triode Q3 is connected to the PWM signal through the first resistor R1, the collector of the second PNP triode Q3 is connected to the base of the second NPN triode Q4, the emitter of the second NPN triode Q4 is grounded, the collector of the second NPN triode Q4 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the gate of the power tube MOSFET through the second resistor R2.

In this embodiment, when the PWM signal is at a high level (i.e., the point a is at a high level), the first NPN transistor Q1 and the first PNP transistor Q2 are turned off and turned on, and the second power supply voltage HVCC stops driving the power transistor MOSFET; at the same time, the second PNP triode Q3 is turned on, and the base of the second NPN triode Q4 is pulled high, so that the second NPN triode Q4 is turned on; at this time, the power transistor MOSFET discharges to ground through the second NPN transistor Q4 to complete the discharging reset of the gate parasitic capacitance of the power transistor MOSFET, wherein the discharging speed is adjusted by the second resistor R2 and the fourth resistor R4.

More specifically, as shown in fig. 3, the reset module 103 further includes: the second filter capacitor C2 and the fifth resistor R5 are connected in parallel between the base of the second NPN type triode Q4 and the ground, and the second filter capacitor C2 and the fifth resistor R5 are connected in parallel between the base of the second NPN type triode Q4 and the ground; the second filter capacitor C2 and the fifth resistor R5 form an RC filter circuit, and the RC filter circuit is configured to filter a base voltage of the second NPN type triode Q4, so as to prevent the second NPN type triode Q4 from being triggered by mistake.

Example two

As shown in fig. 4, the difference between the present embodiment and the first embodiment is that an eighth resistor R8, a diode D1, and a negative feedback module 104 are added to the driving circuit of the present embodiment, wherein the eighth resistor R8 is a part of the control module 101.

One end of the eighth resistor R8 is connected to the first power supply voltage LVCC, and the other end of the eighth resistor R8 is connected to one end of the sixth resistor R6; the anode of the diode D1 is connected to the second power supply voltage HVCC, and the cathode of the diode D1 is connected to the other end of the eighth resistor R8; the negative feedback module 104 is connected between the gate of the power transistor MOSFET and the first control end of the driving module 102, and configured to perform negative feedback control on the second power supply voltage HVCC by adjusting the control voltage (i.e., the voltage at the point B) when the second power supply voltage HVCC fluctuates.

Specifically, as shown in fig. 4, the negative feedback module 104 includes: the driving circuit comprises a third NPN type triode Q5, a ninth resistor R9 and a tenth resistor R10, wherein one end of the ninth resistor R9 is connected to the gate of the power transistor MOSFET, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the base of the third NPN type triode Q5, the other end of the tenth resistor R10 is grounded, the emitter of the third NPN type triode Q5 is grounded, and the collector of the third NPN type triode Q5 is connected to the first control end of the driving module 102.

In this embodiment, the diode D1 plays a role of isolation and reverse connection prevention, and meanwhile, due to the existence of the conduction voltage drop of the diode D1, the voltage at the point D may also be clamped, and if the conduction voltage drop of the diode D1 is 0.7V, the voltage at the point D is clamped at (HVCC-0.7V). The ninth resistor R9 and the tenth resistor R10 form a sampling resistor for sampling the grid voltage of the power tube MOSFET; if the second power supply voltage HVCC suddenly fluctuates to cause the voltage at the point C to increase, thereby causing the gate voltage of the power tube MOSFET to increase, at this time, after sampling, the base current of the third NPN transistor Q5 will increase, so that the collector-emitter current flowing through the third NPN transistor Q5 increases, the current flowing through the sixth resistor R6 will also increase, thereby causing the voltage at the point B to increase, while the currents flowing through the first NPN transistor Q1 and the sixth resistor R6 both increase, which is equivalent to the increase of the load of the second power supply voltage HVCC, so that the voltage fluctuation of the second power supply voltage HVCC will decrease through the diode D1, thereby performing a negative feedback function, and vice versa, finally, the gate voltage of the power tube MOSFET is maintained at a stable level, thereby playing a voltage stabilizing role, and preventing the gate voltage of the power tube MOSFET from being too high due to the fluctuation of the second power supply voltage HVCC, even exceeding the limit value of the power tube MOSFET, thereby damaging the power tube MOSFET.

More specifically, as shown in fig. 4, the negative feedback module 104 includes: and the third filter capacitor C3 is connected between the base of the third NPN type triode Q5 and the ground, and is configured to filter the base voltage of the third NPN type triode Q5 to prevent the third NPN type triode Q5 from being triggered by mistake.

EXAMPLE III

The present embodiment provides a DC-DC power supply system including: the driving circuit according to embodiment one or embodiment two. Of course, the driving circuit described in the first embodiment or the second embodiment can be applied to other products requiring driving of the power tube, such as a motor, besides the DC-DC power supply system described in this embodiment.

Specifically, as shown in fig. 5, the DC-DC power supply system further includes: the power supply system comprises a first power tube MOSFET1, a second power tube MOSFET2, an inductor L1, an input filter capacitor Cin and an output filter capacitor Cout, wherein the drain of the first power tube MOSFET1 is connected with an input voltage Vin, the source of the first power tube MOSFET1 is connected with the drain of the second power tube MOSFET2 and one end of the inductor L1, the gate of the first power tube MOSFET1 is connected with a second resistor in a driving circuit as described in the first embodiment or the second embodiment, the source of the second power tube MOSFET2 is grounded, the gate of the second power tube MOSFET2 is connected with a second resistor in another driving circuit as described in the first embodiment or the second embodiment, the other end of the inductor L1 is used as the output end of the DC-DC power supply system and is used for generating an output voltage Vout, the input filter capacitor Cin is connected between the input voltage Vin and the ground, and the output filter capacitor Cout is connected between the output voltage Vout and the ground Vout. It should be noted that, since the DC-DC power supply system of the present embodiment includes two power transistors, it has two driving circuits for respectively driving the two power transistors, and for convenience of the following description, the driving circuit connected to the gate of the first power transistor MOSFET1 is defined as a first driving circuit, and the driving circuit connected to the gate of the second power transistor MOSFET2 is defined as a second driving circuit.

More specifically, as shown in fig. 6, the DC-DC power supply system further includes: a 1 st pin of the control chip U1 is connected to a 7 th pin through an eleventh resistor R11 and a fourth capacitor C4, a PHASE signal is generated at the 7 th pin, a 2 nd pin is externally connected with an MCU _ PWM signal, a 3 rd pin is externally connected with an MUC _ ENA signal and is connected to a 6 th pin through a twelfth resistor R12, a 4 th pin is externally connected with a power supply voltage VCC and is grounded through a fifth capacitor, a 5 th pin is used for generating a PWM _2 signal, and an 8 th pin is used for generating a PWM _1 signal; the 8 th pin is connected with a first resistor in the first driving circuit, the 5 th pin is connected with a first resistor in the second driving circuit, and the power supply circuit is used for controlling the first power tube MOSFET1 to be switched on and the second power tube MOSFET2 to be switched off based on the two driving circuits when the PWM _1 signal is at a low level and the PWM _2 signal is at a high level, and controlling the first power tube MOSFET1 to be switched off and the second power tube MOSFET2 to be switched on based on the two driving circuits when the PWM _1 signal is at a high level and the PWM _2 signal is at a low level.

In this embodiment, when the first power transistor MOSFET1 is turned on and the second power transistor MOSFET2 is turned off, the input voltage Vin stores energy for the inductor L1 and provides energy for a load; when the first power tube MOSFET1 is turned off and the second power tube MOSFET2 is turned on, the inductor L1 and the output filter capacitor Cout start to discharge to provide energy for the load, and at this time, the second power tube MOSFET2 plays a role of follow current. It should be noted that the driving phase difference between the first power tube MOSFET1 and the second power tube MOSFET2 is 180 °, otherwise, the two power tubes would be turned on simultaneously, and a transient large current would damage the power tubes.

In summary, the driving circuit and the DC-DC power supply system of the present invention provide a brand new MOSFET driving circuit through the design of the control module, the driving module and the reset module, which has the advantages of strong driving capability, small driving voltage drop, and adjustable driving voltage and driving current, can be applied to MOSFET driving application of low-voltage power supply products, and can also drive high-power MOSFETs and meet the requirements of driving voltage amplitude; in addition, the driving circuit has a negative feedback regulation function, can effectively limit the fluctuation of the grid voltage peak value of the MOSFET and ensures the stability of the grid voltage. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims (11)

1. A driver circuit, characterized in that the driver circuit comprises:

the control module is used for carrying out resistance voltage division on the first power supply voltage to generate a control voltage;

the first control end of the driving module is connected with the output end of the control module, the second control end of the driving module is connected with the PWM signal through a first resistor, the input end of the driving module is connected with a second power supply voltage, and the output end of the driving module is connected with the grid electrode of the power tube through a second resistor; the power tube is used for generating a driving voltage based on the second power supply voltage to drive the power tube when the PWM signal is at a low level, wherein the driving voltage is equal to the difference value between the second power supply voltage and the voltage drop between the emitter and the collector of the triode;

the first control end of the reset module is connected with the output end of the control module, the second control end of the reset module is connected with the PWM signal through a first resistor, the input end of the reset module is connected with the grid electrode of the power tube through a second resistor, and the output end of the reset module is grounded; and the power tube is used for discharging and resetting when the PWM signal is at a high level.

2. The driving circuit according to claim 1, wherein the driving module comprises: the base electrode of the first NPN type triode is connected with the output end of the control module, the emitting electrode of the first NPN type triode is connected with the PWM signal through the first resistor, the collecting electrode of the first NPN type triode is connected with the base electrode of the first PNP type triode, the emitting electrode of the first PNP type triode is connected with the second power voltage through the third resistor, and the collecting electrode of the first PNP type triode is connected with the grid electrode of the power tube through the second resistor.

3. The driving circuit of claim 2, wherein the driving module further comprises: and the first filter capacitor is connected between the second power supply voltage and the ground.

4. The driving circuit of claim 1, wherein the reset module comprises: the base electrode of the second PNP type triode is connected with the output end of the control module, the emitting electrode of the second PNP type triode is connected with the PWM signal through the first resistor, the collecting electrode of the second PNP type triode is connected with the base electrode of the second NPN type triode, the emitting electrode of the second NPN type triode is grounded, the collecting electrode of the second NPN type triode is connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the grid electrode of the power tube through the second resistor.

5. The driving circuit of claim 4, wherein the reset module further comprises: the second filter capacitor and the fifth resistor are connected between the base of the second NPN type triode and the ground in parallel.

6. The drive circuit according to any one of claims 1 to 5, wherein the control module comprises: one end of the sixth resistor is connected with the first power voltage, the other end of the sixth resistor is connected with one end of the seventh resistor and serves as the output end of the control module, and the other end of the seventh resistor is grounded.

7. The drive circuit of claim 6, wherein the control module further comprises: one end of the eighth resistor is connected with the first power supply voltage, and the other end of the eighth resistor is connected with one end of the sixth resistor; at this time, the driving circuit further includes: and the anode of the diode is connected with the second power supply voltage, and the cathode of the diode is connected with the other end of the eighth resistor.

8. The driving circuit according to claim 7, further comprising: and the negative feedback module is connected between the grid of the power tube and the first control end of the driving module and is used for performing negative feedback control on the second power supply voltage by adjusting the control voltage when the second power supply voltage fluctuates.

9. The driving circuit of claim 8, wherein the negative feedback module comprises: the power transistor comprises a third NPN type triode, a ninth resistor and a tenth resistor, wherein one end of the ninth resistor is connected with the grid electrode of the power transistor, the other end of the ninth resistor is connected with one end of the tenth resistor and the base electrode of the third NPN type triode, the other end of the tenth resistor is grounded, the emitting electrode of the third NPN type triode is grounded, and the collector electrode of the third NPN type triode is connected with the first control end of the driving module.

10. The driving circuit of claim 9, wherein the negative feedback module comprises: and the third filter capacitor is connected between the base of the third NPN type triode and the ground.

11. A DC-DC power supply system, characterized in that the DC-DC power supply system comprises: a driver circuit as claimed in any one of claims 1 to 10.

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