CN116094292A - D-type gallium nitride switch driving circuit and switching power supply circuit - Google Patents

Abstract

The invention provides a D-type gallium nitride switch driving circuit and a switching power supply circuit, wherein the drain electrode of a D-type gallium nitride switch is connected with a first voltage, the source electrode of the D-type gallium nitride switch is respectively coupled to a first end of a switch module and a first end of a first capacitor, the grid electrode of the D-type gallium nitride switch is coupled to a first end of a first control module, a second end of the first control module is coupled to a second end of the first capacitor, and a second control module is coupled to a control end of the switch module, the second end of the first capacitor and a third end of the switch module are grounded, so that the second control module outputs a control signal to control the on and off of the switch module, the on and off of the D-type gallium nitride switch is controlled, meanwhile, the on speed of the D-type gallium nitride switch is independently regulated by the first control module, the voltage stress of a subsequent circuit can be reduced by the lower on speed, and the EMI characteristics are improved.

Description

D-type gallium nitride switch driving circuit and switching power supply circuit

technical field

The invention relates to the field of power supplies, in particular to a D-type gallium nitride switch drive circuit and a switch power supply circuit.

Background technique

In recent years, gallium nitride switching tubes have been widely used in the field of switching power supply topology, especially in the field of high-power power supply, AC/DC switching power supply and other fields.

Currently commonly used switching power supply topology circuits, including: Buck circuit, Boost circuit, Buck-Boost circuit, forward circuit, flyback circuit, half-bridge power circuit, etc., are widely used in equipment and devices that need to convert voltage system.

The primary GaN power tube of the existing switching power supply topology circuit generally adopts the E-type GaN switch tube. The driving circuit is mature and the switching speed is adjustable, but it is more suitable for soft switching conditions under high frequency conditions; When limited to topology or control strategy and can only achieve hard switching, the D-type GaN switch has more advantages in terms of on-state loss, but the D-type GaN switch is a normally-on device and needs to be connected in series. Close the switch, and then control the on-off of the D-type GaN switch by controlling the on-off of the normally-closed switch, and the turn-on speed of the D-type GaN switch is fast and difficult to control, which will lead to excessive voltage stress in the subsequent circuit high. In this case, the switch of the D-type GaN switch can be adjusted by adjusting the switching speed of the normally closed switch or adjusting the capacitance value of the capacitor connected between the gate and the source of the D-type GaN switch. Speed, but this approach has a limited impact on the turn-on speed of the D-type GaN switch tube, but has a greater impact on its turn-off speed, which has a greater impact on efficiency.

Therefore, how to control the turn-on speed of the D-type GaN switch without affecting the turn-off speed, so as to reduce the voltage stress of the subsequent circuit and improve the EMI characteristics, has become an urgent technical problem in the industry. .

Contents of the invention

The present invention provides a D-type GaN switch driving circuit and a switching power supply circuit to solve the problem of controlling the turn-on speed of the D-type GaN switch tube without affecting the turn-off speed of the D-type GaN switch tube, so as to reduce the cost of subsequent circuits. Voltage stress, technical issues for improving EMI characteristics.

According to the first aspect of the present invention, a D-type GaN switch driving circuit is provided, including: a D-type GaN switch, a first control module, a second control module, a first capacitor, and a switch module; wherein:

The drain of the D-type GaN switch is connected to a first voltage, and the source of the D-type GaN switch is respectively coupled to the first end of the switch module and the first end of the first capacitor, Its gate is coupled to the first terminal of the first control module, the second terminal of the first control module is coupled to the second terminal of the first capacitor, and the second control module is coupled to the The control end of the switch module, the second end of the first capacitor and the third end of the switch module are grounded;

The second control module is used to output a control signal to control the turn-on and turn-off of the switch module, so as to control the turn-on and turn-off of the D-type gallium nitride switch;

The first control module is used to adjust the turn-on speed of the D-type GaN switch.

Optionally, the first control module is further configured to adjust the turn-off speed of the D-type GaN switch.

Optionally, the first control module includes a turn-on speed control module and a turn-off speed control module connected in parallel, wherein:

The turn-on speed control module is used to adjust the turn-on speed of the D-type GaN switch;

The turn-off speed control module is used to adjust the turn-off speed of the D-type GaN switch.

Optionally, the turn-on speed control module includes a first resistor; wherein:

The gate of the D-type gallium nitride switch is coupled to the first terminal of the first resistor, and the second terminal of the first resistor is also coupled to the second terminal of the first capacitor;

The first resistor is used to adjust the turn-on speed of the D-type GaN switch.

Optionally, the turn-off speed control module includes a first diode and a second resistor;

The first end of the second resistor is coupled to the gate of the D-type gallium nitride switch, and the second end is coupled to the anode of the first diode; the cathode of the first diode coupled to the second end of the first resistor;

The second resistor is used to adjust the turn-off speed of the D-type GaN switch.

Optionally, a clamping Zener diode is also included;

The anode of the clamping Zener diode is coupled to the first end of the first resistor, and the cathode of the clamping Zener diode is coupled to the source of the D-type GaN switch.

Optionally, the switch module is a first NMOS switch tube;

The drain of the first NMOS switch transistor is coupled to the source of the D-type GaN switch, its gate is coupled to the second control module, and its source is grounded.

Optionally, a sampling module is also included, and the sampling module includes a current detection resistor and a second NMOS switch tube;

The first end of the second control module is respectively coupled to the gate of the second NMOS switch and the gate of the first NMOS switch, and its second end is coupled to the second NMOS switch. The drain, its third end is coupled to the first end of the current detection resistor, its fourth end is coupled to the drain of the first NMOS switch tube, and its fifth end is grounded; the current detection resistor The second end of the second end and the source of the second NMOS switch tube are respectively grounded;

The first end of the second control module is used to output the control signal, and control the turn-on and turn-off of the first NMOS switch and the second NMOS switch, and the second end and the fourth end are used for to output the same voltage, so that the second NMOS switch tube and the first NMOS switch tube form a current mirror; and the second control module is also used to mirror the current flowing through the second NMOS switch tube to the current detection resistor, so that the current flowing through the current detection resistor is equal to the current flowing through the second NMOS switch tube.

Optionally, the width-to-length ratio of the first NMOS switch transistor is greater than the width-to-length ratio of the second NMOS switch transistor.

Optionally, the input terminal of the second control module receives an input signal; the second control module outputs a corresponding control signal according to the input signal, wherein:

If the input signal is high level, the control signal is an adapted high level signal;

If the input signal is low level, the control signal is an adapted low level signal.

Optionally, the output capacitor is also included;

The first terminal of the output capacitor is coupled to the sixth terminal of the second control module, and the second terminal of the output capacitor is grounded.

Optionally, a high-voltage startup module is also included; the high-voltage startup module includes a second diode, a constant current source, an LDO module, and an input capacitor;

The source of the D-type GaN switch is coupled to the anode of the second diode, the cathode of the second diode is coupled to the first end of the constant current source, and the constant current The second terminal of the source is coupled to the first terminal of the LDO module, the third terminal thereof is coupled to the seventh terminal of the second control module, and the second terminals of the LDO module are respectively coupled to the first The eighth end of the second control module and the first end of the input capacitor, the second end of the input capacitor is grounded; wherein,

The seventh terminal of the second control module is used to control the opening and closing of the constant current source;

The input capacitor is used for powering the second control module.

According to the second aspect of the present invention, there is provided a switching power supply circuit, including the D-type gallium nitride switch driving circuit, RCD absorbing circuit and primary winding provided by any one of the first aspect of the present invention;

The first end of the primary winding is coupled to the first end of the RCD snubber circuit, and the second end thereof is respectively coupled to the second end of the RCD snubber circuit and the drain of the D-type GaN switch .

Optionally, the RCD snubber circuit includes a second capacitor, a third resistor, and a third diode;

The first end of the primary winding is respectively coupled to the first end of the second capacitor and the first end of the third resistor, and the second end of the second capacitor is coupled to the third resistor The second terminal, the second terminal of the third resistor is coupled to the cathode of the third diode, and the anode of the third diode is coupled to the second terminal of the primary winding.

Optionally, a power supply side capacitor is also included; the first terminal of the primary winding is coupled to the first terminal of the power supply side capacitor, and the second terminal of the power supply side capacitor is grounded.

Optionally, secondary windings are also included.

In the D-type GaN switch driving circuit and the switching power supply circuit provided by the present invention, the drain of the D-type GaN switch is connected to the first voltage, and its source is respectively coupled to the first terminal of the switch module and the first capacitor The first terminal of the first control module, the gate of which is coupled to the first terminal of the first control module, the second terminal of the first control module is coupled to the second terminal of the first capacitor, and the second control module is coupled to the control of the switch module end, the second end of the first capacitor and the third end of the switch module are grounded, so that the second control module outputs a control signal to control the turn-on and turn-off of the switch module, thereby controlling the turn-off and turn-off of the D-type GaN switch. It is turned on without affecting its turn-off speed, which ensures the efficiency. At the same time, the turn-on speed of the D-type GaN switch is adjusted through the first control module to reduce the voltage stress of the subsequent circuit and improve the EMI characteristics.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a first schematic diagram of the structure of a D-type gallium nitride switch driving circuit in an embodiment of the present invention;

FIG. 2 is a second structural schematic diagram of a D-type gallium nitride switch driving circuit in an embodiment of the present invention;

3 is a schematic structural diagram of a D-type gallium nitride switch drive circuit in an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a switching power supply circuit in another embodiment of the present invention;

Fig. 5 is a schematic waveform diagram of the switching power supply circuit shown in Fig. 4;

Fig. 6 is a schematic structural diagram of a switching power supply circuit in the prior art;

Fig. 7 is a schematic waveform diagram of the switching power supply circuit shown in Fig. 6;

Explanation of reference signs:

10 - the first control module;

20 - the second control module;

101 - activate the speed control module;

102 - turn off the speed control module;

Vd-the first voltage;

N-GAN-D GaN switch;

Cgs - the second parasitic capacitance;

Main Fet-switch module;

Sense Fet-the second NMOS switch tube;

D1 - the first diode;

D2 - the second diode;

D3 - the third diode;

D4 fourth diode;

R1-the first resistor;

R2-the second resistor;

R3-the third resistor;

C1-the first capacitor;

C2-the second capacitor;

DZ1-clamp Zener diode;

Cvcco - output capacitance;

Cvcci - input capacitance;

Istart - constant current source.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and not necessarily Used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The technical solution of the present invention will be described in detail below with specific examples. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

In view of the prior art, it is difficult to control the turn-on speed of the D-type GaN switch tube while ensuring the efficiency. The present invention provides a D-type gallium nitride switch driving circuit and a switching power supply circuit. The drain of the D-type gallium nitride switch is connected to the first voltage, and its source is respectively coupled to the first end of the switch module and the first The first terminal of the capacitor, the gate of which is coupled to the first terminal of the first control module, the second terminal of the first control module is coupled to the second terminal of the first capacitor, and the second control module is coupled to the switch module The control terminal, the second terminal of the first capacitor and the third terminal of the switch module are grounded, so that the second control module outputs a control signal to control the on and off of the switch module, thereby controlling the conduction of the D-type GaN switch At the same time, the turn-on speed of the D-type GaN switch is independently adjusted by the first control module. The lower turn-on speed can reduce the voltage stress of the subsequent circuit and improve the EMI characteristics.

Please refer to FIG. 1 , an embodiment of the present invention provides a D-type gallium nitride switch drive circuit, including: a D-type gallium nitride switch D-GAN, a first control module 10, a second control module 20, and a first capacitor C1 and switch module SW; where:

The drain of the D-type gallium nitride switch D-GAN is connected to the first voltage Vd, and the source of the D-type gallium nitride switch D-GAN is respectively coupled to the first terminal of the switch module SW and the The first terminal of the first capacitor C1, the gate of which is coupled to the first terminal of the first control module 10, and the second terminal of the first control module 10 is coupled to the second terminal of the first capacitor C1. Terminal, the second control module 20 is coupled to the control terminal of the switch module SW, the second terminal of the first capacitor C1 and the third terminal of the switch module SW are grounded;

The second control module 20 is used to output a control signal to control the on and off of the switch module SW to control the on and off of the D-type gallium nitride switch D-GAN, because, The D-type GaN switch D-GAN is a normally-on device, but in actual power supply applications, the terminal equipment usually requires the device to be in the normally-off mode, so that when the control of the switch fails, the device can still be turned off state to ensure system security; and from the circuit structure shown in Figure 1, when the D-GaN switch D-GAN gate voltage is 0 and the gate-source voltage is less than its pinch-off threshold, it works in positive to the blocking mode; when the switch module SW is turned on, the gate-source voltage of the D-type gallium nitride switch D-GAN is zero, and there is a 2DEG channel between the drain and the source, and the D-type gallium nitride switch D-GAN has a 2DEG channel. The gallium nitride switch D-GAN will be turned on, so controlling the on-off of the switch module SW can control the on-off of the D-type gallium nitride switch D-GAN.

The first control module 10 is used to adjust the turn-on speed of the D-GaN switch D-GAN. If the turn-on speed of the D-type gallium nitride switch D-GAN is too fast, the current flowing through the switch module SW will overshoot in a very short time, which will easily damage the switch module SW and cause EMI to exceed the standard or even The problem of destructive oscillations. However, the present invention can adjust the turn-on speed of the D-type gallium nitride switch D-GAN through the first control module 10, thereby effectively protecting the switch module SW and solving the problem of EMI.

Wherein, there is a first parasitic capacitance Cds between the drain and source of the D-type gallium nitride switch D-GAN, and the first capacitance C1 is used to form a voltage divider with the first parasitic capacitance Cds (not shown in the figure), In order to reduce the voltage of the first end of the switch module SW when the D-GaN switch D-GAN is turned off.

As a preferred implementation manner, please refer to FIG. 1 , the D-GaN switch D-GAN drive circuit also includes a clamping Zener diode DZ1;

The anode of the clamping Zener diode DZ1 is coupled to the first end of the first resistor, and the cathode of the clamping Zener diode DZ1 is coupled to the source of the D-type GaN switch D-GAN .

For gallium nitride power transistors, a faster turn-off speed can improve circuit efficiency. In one embodiment, in order to balance EMI characteristics and circuit efficiency, the first control module 10 is also used to adjust the D-type gallium nitride Please refer to FIG. 2 for the turn-off speed of the switch D-GAN. The first control module 10 includes a turn-on speed control module 101 and a turn-off speed control module 102 connected in parallel, wherein:

The turn-on speed control module 101 is used to adjust the turn-on speed of the D-type gallium nitride switch D-GAN;

The turn-off speed control module 102 is used to adjust the turn-off speed of the D-GaN switch D-GAN.

In one example, as shown in FIG. 2, the turn-on speed control module 101 includes a first resistor R1; wherein:

The gate of the D-type gallium nitride switch D-GAN is coupled to the first terminal of the first resistor R1, and the second terminal of the first resistor R1 is also coupled to the first terminal of the first capacitor C1. Two ends;

The first resistor R1 is used to adjust the turn-on speed of the D-type gallium nitride switch D-GAN, specifically, please refer to FIG. 2, because there is an The second parasitic capacitance Cgs, the voltage on the second parasitic capacitance Cgs (that is, the gate-source voltage Vgs of the D-type gallium nitride switch D-GAN) is discharged through the first control module 10, as shown in FIG. 2 In the example of , the second parasitic capacitance Cgs and the first resistor R1 form a discharge circuit when the D-type gallium nitride switch D-GAN is turned on, and the resistance value of the first resistor R1 can be reduced by increasing the resistance value of the first resistor R1. The turn-on speed of the D-type gallium nitride switch D-GAN, and the lower turn-on speed can reduce the voltage stress of subsequent circuits, improve EMI, and improve system reliability.

In this case, in an example, please refer to FIG. 2 , the turn-off speed control module 102 includes a first diode D1 and a second resistor R2;

The first end of the second resistor R2 is coupled to the gate of the D-type GaN switch D-GAN, and the second end is coupled to the anode of the first diode D1; the first The cathode of the diode D1 is coupled to the second end of the first resistor R1;

The second resistor R2 is used to adjust the turn-off speed of the D-type GaN switch D-GAN, specifically, when the switch module SW is turned off, the D-type GaN switch D-GAN The source voltage starts to rise, and the voltage on the second parasitic capacitor Cgs starts to be charged through the first control module 10, when the gate-source voltage of the D-type gallium nitride switch D-GAN is lower than the pinch-off voltage threshold Afterwards, the D-type gallium nitride switch D-GAN starts to turn off. In the example shown in FIG. 2, the second parasitic capacitance Cgs, the second resistor R2 and the first diode D1 form For the charging circuit when it is turned off, reducing the resistance value of the second resistor R2 can speed up the turn-off speed of the D-type gallium nitride switch D-GAN, and improve the system efficiency. Wherein, the resistance value of the second resistor R2 is much smaller than the resistance value of R1.

As a preferred implementation manner, the resistance value of the second resistor R2 is set to 0, so that the turn-off speed of the D-type gallium nitride switch D-GAN is the fastest.

As an example, the switch module SW may be a MOS switch tube, and the second control module 20 is connected to the gate of the MOS tube and sends a control signal to control the on-off of the MOS tube. Certainly, the present invention is not limited thereto, and in other examples, the switch module SW may also choose a triode or other normally closed switch devices.

In one embodiment, please refer to FIG. 3, the switch module SW is the first NMOS switch Main Fet;

The drain of the first NMOS switch Main Fet is coupled to the source of the D-type gallium nitride switch D-GAN, its gate is coupled to the second control module 20, and its source is grounded.

In order to sample the current flowing through the D-type gallium nitride switch D-GAN, in an implementation manner, please refer to FIG. 3, the D-type gallium nitride switch D-GAN drive circuit also includes a sampling module 30, the The sampling module 30 includes a current detection resistor Rsense and a second NMOS switch tube Sense Fet;

The first end of the second control module 20 is respectively coupled to the gate of the second NMOS switch Sense Fet and the gate of the first NMOS switch Main Fet, and its second end is coupled to the The drain of the second NMOS switch SenseFet, the third terminal thereof is coupled to the first terminal of the current detection resistor Rsense, the fourth terminal thereof is coupled to the drain of the first NMOS switch Main Fet, and the third terminal thereof is coupled to the drain of the first NMOS switch Main Fet. The five terminals are grounded; the second terminal of the current detection resistor Rsense and the source of the second NMOS switch Sense Fet are respectively grounded;

The first end of the second control module 20 is used to output the control signal to control the turn-on and turn-off of the first NMOS switch tube Main Fet and the second NMOS switch tube Sense Fet. And the fourth end is used to output the same voltage, so that the second NMOS switch tube Sense Fet and the first NMOS switch tube Main Fet form a current mirror; and the second control module 20 is also used to flow through The current of the second NMOS switch Sense Fet is mirrored to the current detection resistor Rsense, so that the current flowing through the current detection resistor Rsense is equal to the current flowing through the second NMOS switch Sense Fet.

As a preferred implementation manner, the width-to-length ratio of the first NMOS switch transistor Main Fet is greater than the width-to-length ratio of the second NMOS switch transistor Sense Fet.

Since the current flowing through the first NMOS switch Main Fet is almost equal to the current flowing through the D-type gallium nitride switch D-GAN, the current flowing through the first NMOS switch Main Fet can be obtained by sampling the current of the first NMOS switch Main Fet. current through the D-GaN switch D-GAN. Since the Vgs voltage and the Vds voltage of the first NMOS switch tube Main Fet are respectively equal to the Vgs voltage and the Vds voltage of the second NMOS switch tube Sense Fet, the first NMOS switch tube Main Fet and the second NMOS switch tube The Ids current ratio of the switch tube Sense Fet will be proportional to its width-to-length ratio, so as long as the current flowing through the second NMOS switch tube Sense Fet is sampled, the current flowing through the first NMOS switch tube Main Fet can be known, thereby obtaining The current of the D-type gallium nitride switch D-GAN, and because the second control module 20 mirrors the current flowing through the second NMOS switch Sense Fet to the current detection resistor Rsense, the current detection resistor Rsense The current left on Rsense is equal to the current flowing through the second NMOS switch tube Sense Fet; and after the circuit design is fixed, the resistance value of the current detection resistor Rsense is known, so measure the current at both ends of the current detection resistor Rsense The voltage can obtain the current flowing in the second NMOS switch tube Sense Fet, and then obtain the current of the first NMOS switch tube Main Fet.

Given the current I ₁ flowing through the first NMOS switch Main Fet, the current I ₂ flowing through the second NMOS switch Sense Fet, the resistance value of the current sensing resistor Rsense, the current sensing resistor Rsense The voltage Vcs at both ends has the following relationship:

Vcs=I ₂ ·Rsense=K·I ₁ ·Rsense

Wherein, K is the width-to-length ratio of the second NMOS switch Sense Fet to the first NMOS switch Main Fet, usually K is one thousandth, so the loss on the current detection resistor Rsense is relatively low.

As a further preferred implementation manner, the first NMOS switch tube Main Fet and the second NMOS switch tube Sense Fet are integrated on the same substrate, and the processes of the MOS switch tubes are the same. In this case, for the convenience of measuring the voltage of the current detection resistor Rsense, the current detection resistor Rsense is an off-chip resistor.

As a preferred embodiment, the second control module 20 performs level processing of the corresponding signal according to the external signal, so that the level of the control signal output by the second control module 20 is adapted to the level that the subsequent circuit can receive. Level, please refer to FIG. 3, the input terminal of the second control module 20 receives the input signal PWM; the second control module 20 outputs a corresponding control signal according to the input signal PWM, wherein:

If the input signal PWM is at a high level, the control signal is an adapted high level signal;

If the input signal PWM is low level, the control signal is an adapted low level signal.

In this case, in an implementation manner, the D-type gallium nitride switch D-GAN drive circuit further includes an output capacitor Cvcco;

The first terminal of the output capacitor Cvcco is coupled to the sixth terminal of the second control module 20 , and the second terminal of the output capacitor Cvcco is grounded.

As a preferred embodiment, the D-type gallium nitride switch D-GAN drive circuit also includes a high-voltage start module; the high-voltage start module includes a second diode D2, a constant current source Istart, an LDO module, and an input capacitor Cvcci ;

The source of the D-type gallium nitride switch D-GAN is coupled to the anode of the second diode D2, and the cathode of the second diode D2 is coupled to the first electrode of the constant current source Istart. end, the second end of the constant current source Istart is coupled to the first end of the LDO module, the third end is coupled to the seventh end of the second control module 20, the second end of the LDO module Terminals are respectively coupled to the eighth terminal of the second control module 20 and the first terminal of the input capacitor Cvcci, and the second terminal of the input capacitor Cvcci is grounded; wherein,

The seventh end of the second control module 20 is used to control the opening and closing of the constant current source Istart;

The input capacitor Cvcci is used for powering the second control module 20 .

When the circuit starts, the Main Fet of the first NMOS switch is in the off state, the gate voltage of the D-type gallium nitride switch D-GAN is zero, and the source of the D-type gallium nitride switch D-GAN The voltage gradually rises, and when the Vgs voltage of the D-type GaN switch D-GAN is its pinch-off voltage Vth, the D-type GaN switch D-GAN is turned off, and at this time the D-type GaN The gate voltage of the switch D-GAN is 0, and its source voltage is Vth. At this time, the constant current source Istart takes power from the source of the D-GAN, and charges the input capacitor Cvcci through the LDO module. When When the voltage of the input capacitor Cvcci is the starting voltage of the second control module 20, the second control module 20 enters the working state, and the second control module 20 outputs a corresponding shutdown control signal to turn off the constant current source Istart, Complete self-pick-up electric start. The voltage on the input capacitor Cvcci can also be used as a voltage source for other peripheral circuits.

In addition, an embodiment of the present invention also provides a switching power supply circuit, please refer to FIG. 4 , which includes the above-mentioned D-type gallium nitride switch driving circuit, RCD absorbing circuit 40 and primary winding Np;

The first end of the primary winding Np is coupled to the first end of the RCD snubber circuit 40, and the second end thereof is respectively coupled to the second end of the RCD snubber circuit 40 and the D-type GaN switch Drain of D-GAN.

In one example, please refer to FIG. 4 , the RCD snubbing circuit 40 includes a second capacitor C2, a third resistor R3, and a third diode D3;

The first end of the primary winding Np is respectively coupled to the first end of the second capacitor C2 and the first end of the third resistor R3, and the second end of the second capacitor C2 is coupled to the The second end of the third resistor R3, the second end of the third resistor R3 is coupled to the cathode of the third diode D3, and the anode of the third diode D3 is coupled to the primary winding The second end of Np.

As an implementation manner, please refer to FIG. 4 , the switching power supply circuit further includes a secondary winding Ns.

As a preferred implementation manner, please refer to FIG. 4, the switching power supply circuit further includes a power supply side capacitor Cin; the first end of the primary winding Np is coupled to the first end of the power supply side capacitor Cin, the power supply The second terminal of the side capacitor Cin is grounded.

Please refer to FIG. 4 , the secondary winding Ns of the switching power supply circuit further includes, for example, a rectifier diode D4 , a third capacitor C3 and a fourth resistor R4 .

Wherein, the circuit configurations on the side of the primary winding Np and the side of the secondary winding Ns are the same as the existing conventional circuits, and will not be repeated here.

Now compare the D-type GaN switch drive circuit of the present invention with the working effect of the existing D-GaN switch drive circuit in the switching power supply circuit in conjunction with the waveform diagrams shown in Figure 5 and Figure 7, wherein Figure 5 The waveform diagram shown in Figure 4 is the working effect in the switching power supply circuit, and the waveform diagram shown in Figure 7 is the working effect of the existing D-type GaN switching drive circuit shown in Figure 6 in the switching power supply circuit , the details are as follows:

PWM, can be understood as the control signal output by the second control module 20;

Vd-gan can be understood as the drain voltage of the D-type gallium nitride switch D-GAN;

Vd-mos can be understood as the drain voltage of the first NMOS switching tube Main Fet;

Ids can be understood as the current flowing through the first NMOS switch Main Fet;

Vcs can be understood as the voltage at the first end of the current detection resistor Rsense;

Vd2 can be understood as the voltage of the rectifier diode D4 on the side of the secondary winding Ns;

Wherein, the waveform of the current flowing through the first NMOS switch Main Fet is similar to the voltage of the first terminal of the current detection resistor Rsense, and is shown as the same waveform in FIG. 5 and FIG. 7 .

Please refer to FIG. 6, the existing D-type GaN switch driving circuit can adjust the resistance value of the resistor Rg and/or adjust the capacitance of the capacitor C1 connected between the gate and the source of the D-type GaN switch. value, and then adjust the switching speed of the D-type GaN switch, but this approach has a limited impact on the turn-on speed of the D-type GaN switch, but has a greater impact on its turn-off speed, which has a greater impact on the efficiency. Influence. Please refer to the drain voltage waveform of the first NMOS switch Main Fet in FIG. 7, the current waveform flowing through the first NMOS switch Main Fet, the voltage waveform of the current detection resistor Rsense, and the side of the secondary winding Ns The voltage waveform of the rectifier diode D4, when the D-type gallium nitride switch D-GAN is turned on, its drain voltage and the drain voltage of the first NMOS switch tube Main Fet decrease, but the first NMOS The current stress of the switching tube Main Fet, the voltage stress of the current detection resistor Rsense, and the voltage stress of the rectifier diode D4 on the side of the secondary winding Ns are relatively high, and the rectifier diode D4 on the side of the secondary winding Ns can also detect relatively high High voltage spikes have high voltage stress, and the overshoot of current and voltage will cause EMI to exceed the standard, affecting system safety and reliability;

In the D-GaN switch drive circuit provided by the present invention, the first resistor R1 can reduce the turn-on speed of the D-GaN switch D-GAN without affecting its turn-off speed, thereby ensuring efficiency. Please refer to the drain voltage waveform of the first NMOS switch Main Fet in FIG. 5, the current waveform flowing through the first NMOS switch Main Fet, the voltage waveform of the current detection resistor Rsense, and the side of the secondary winding Ns The voltage waveform of the rectifier diode D4, when the D-type gallium nitride switch D-GAN is turned on, its drain voltage and the voltage of the drain voltage of the first NMOS switch Main Fet decrease, and the first NMOS switch The current stress on the Main Fet, the voltage stress on the current sensing resistor Rsense, and the voltage stress on the rectifier diode D4 on the Ns side of the secondary winding are lower, and a lower voltage can be detected by the rectifier diode D4 on the Ns side of the secondary winding Spike, its voltage stress is low, which effectively prevents the overshoot of current and voltage, improves EMI characteristics, and improves the safety and reliability of the system.

To sum up, in the D-type GaN switch driving circuit and the switching power supply circuit provided by the present invention, the drain of the D-type GaN switch is connected to the first voltage, and the source is respectively coupled to the first voltage of the switch module. terminal and the first terminal of the first capacitor, the gate of which is coupled to the first terminal of the first control module, the second terminal of the first control module is coupled to the second terminal of the first capacitor, and the second control module is coupled to To the control terminal of the switch module, the second terminal of the first capacitor and the third terminal of the switch module are grounded, so that the second control module outputs a control signal to control the on and off of the switch module, thereby controlling the D-type gallium nitride The switch is turned on and off, and at the same time, the turn-on speed of the D-type GaN switch is independently adjusted through the first control module. The lower turn-on speed can reduce the voltage stress of the subsequent circuit and improve the EMI characteristics.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (16)

1. A D-type gallium nitride switch drive circuit, characterized in that it includes: a D-type gallium nitride switch, a first control module, a second control module, a first capacitor, and a switch module; wherein: The drain of the D-type GaN switch is connected to a first voltage, and the source of the D-type GaN switch is respectively coupled to the first end of the switch module and the first end of the first capacitor, Its gate is coupled to the first terminal of the first control module, the second terminal of the first control module is coupled to the second terminal of the first capacitor, and the second control module is coupled to the The control end of the switch module, the second end of the first capacitor and the third end of the switch module are grounded; The second control module is used to output a control signal to control the turn-on and turn-off of the switch module, so as to control the turn-on and turn-off of the D-type gallium nitride switch; The first control module is used to adjust the turn-on speed of the D-type GaN switch. 2 . The D-type GaN switch driving circuit according to claim 1 , wherein the first control module is further used to adjust the turn-off speed of the D-type GaN switch. 3 . 3. The D-type gallium nitride switch driving circuit according to claim 2, wherein the first control module includes a turn-on speed control module and a turn-off speed control module connected in parallel, wherein: The turn-on speed control module is used to adjust the turn-on speed of the D-type GaN switch; The turn-off speed control module is used to adjust the turn-off speed of the D-type GaN switch. 4. The D-type gallium nitride switch driving circuit according to claim 3, wherein the turn-on speed control module includes a first resistor; wherein: The gate of the D-type gallium nitride switch is coupled to the first terminal of the first resistor, and the second terminal of the first resistor is also coupled to the second terminal of the first capacitor; The first resistor is used to adjust the turn-on speed of the D-type GaN switch. 5. The D-type gallium nitride switch drive circuit according to claim 4, wherein the turn-off speed control module comprises a first diode and a second resistor; The first end of the second resistor is coupled to the gate of the D-type gallium nitride switch, and the second end is coupled to the anode of the first diode; the cathode of the first diode coupled to the second end of the first resistor; The second resistor is used to adjust the turn-off speed of the D-type GaN switch. 6. The D-type gallium nitride switch driving circuit according to claim 4, further comprising a clamping Zener diode; The anode of the clamping Zener diode is coupled to the first end of the first resistor, and the cathode of the clamping Zener diode is coupled to the source of the D-type GaN switch. 7. The D-type gallium nitride switch drive circuit according to claim 1, wherein the switch module is a first NMOS switch tube; The drain of the first NMOS switch transistor is coupled to the source of the D-type GaN switch, its gate is coupled to the second control module, and its source is grounded. 8. The D-type gallium nitride switch drive circuit according to claim 7, further comprising a sampling module, the sampling module comprising a current detection resistor and a second NMOS switch tube; The first end of the second control module is respectively coupled to the gate of the second NMOS switch and the gate of the first NMOS switch, and its second end is coupled to the second NMOS switch. The drain, its third end is coupled to the first end of the current detection resistor, its fourth end is coupled to the drain of the first NMOS switch tube, and its fifth end is grounded; the current detection resistor The second end of the second end and the source of the second NMOS switch tube are respectively grounded; The first end of the second control module is used to output the control signal, and control the turn-on and turn-off of the first NMOS switch and the second NMOS switch, and the second end and the fourth end are used for to output the same voltage, so that the second NMOS switch tube and the first NMOS switch tube form a current mirror; and the second control module is also used to mirror the current flowing through the second NMOS switch tube to the current detection resistor, so that the current flowing through the current detection resistor is equal to the current flowing through the second NMOS switch tube. 9 . The D-type GaN switch driving circuit according to claim 8 , wherein a width-to-length ratio of the first NMOS switch transistor is greater than a width-to-length ratio of the second NMOS switch transistor. 10. The D-type GaN switch driving circuit according to claim 8, wherein the input terminal of the second control module receives an input signal; and the second control module outputs a corresponding control signals, where: If the input signal is high level, the control signal is an adapted high level signal; If the input signal is low level, the control signal is an adapted low level signal. 11. The D-type gallium nitride switch driving circuit according to claim 8, further comprising an output capacitor; The first terminal of the output capacitor is coupled to the sixth terminal of the second control module, and the second terminal of the output capacitor is grounded. 12. The D-type gallium nitride switch drive circuit according to claim 8, further comprising a high-voltage startup module; the high-voltage startup module includes a second diode, a constant current source, an LDO module, and an input capacitor; The source of the D-type GaN switch is coupled to the anode of the second diode, the cathode of the second diode is coupled to the first end of the constant current source, and the constant current The second terminal of the source is coupled to the first terminal of the LDO module, the third terminal thereof is coupled to the seventh terminal of the second control module, and the second terminals of the LDO module are respectively coupled to the first The eighth end of the second control module and the first end of the input capacitor, the second end of the input capacitor is grounded; wherein, The seventh terminal of the second control module is used to control the opening and closing of the constant current source; The input capacitor is used for powering the second control module. 13. A switching power supply circuit, characterized in that it comprises the D-type gallium nitride switch drive circuit, RCD snubber circuit and primary winding according to any one of claims 1 to 12; The first end of the primary winding is coupled to the first end of the RCD snubber circuit, and the second end thereof is respectively coupled to the second end of the RCD snubber circuit and the drain of the D-type GaN switch . 14. The switching power supply circuit according to claim 13, wherein the RCD snubber circuit comprises a second capacitor, a third resistor, and a third diode; The first end of the primary winding is respectively coupled to the first end of the second capacitor and the first end of the third resistor, and the second end of the second capacitor is coupled to the third resistor The second terminal, the second terminal of the third resistor is coupled to the cathode of the third diode, and the anode of the third diode is coupled to the second terminal of the primary winding. 15. The switching power supply circuit according to claim 13, further comprising a power supply side capacitance; the first end of the primary winding is coupled to the first end of the power supply side capacitance, and the power supply side capacitance The second end is grounded. 16. The switching power supply circuit according to claim 13, further comprising a secondary winding.

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