GaN HEMT power device drive circuit and switching power supply circuit

Abstract

The present application discloses a driving circuit and a switching power supply circuit of a GaN HEMT power device, which are applied in the field of power electronics technology to solve the problem that the driving circuit of the GaN HEMT power device in the prior art is relatively complicated. Specifically, it includes: a voltage conversion circuit composed of a first switch module, an inductive energy storage module, at least one positive end capacitive energy storage module, at least one negative end capacitive energy storage module and a controller, at least one first driving module and at least one second driving module. In this way, by controlling the first switch module to switch between the first state and the second state, it is possible to simultaneously generate negative voltage and positive voltage through the same voltage conversion circuit, so as to simultaneously power the first driving module driving the external switch tube and the second driving module driving the GaN HEMT power device, without the need to additionally set up a linear regulator, simplifying the circuit setting and improving the efficiency of the driving circuit.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a driving circuit and a switching power supply circuit of a GaN HEMT power device. Background Art

[0002] Compared with traditional silicon (Si) power devices, the use of wide bandgap semiconductor devices represented by GaN can significantly reduce the energy loss of the power system and improve the conversion efficiency. GaN high electron mobility transistor (HEMT) is naturally suitable for making high-voltage and high-frequency power switches due to its excellent characteristics such as high withstand voltage, low on-resistance and high switching speed. But at the same time, the gate withstand voltage range of GaN HEMT is narrow, the threshold voltage stability is poor, and the high-frequency switching process is extremely sensitive to parasitics. The slightest carelessness will cause the gate to lose control and cause device damage. Therefore, the importance of driver chip design matching GaN HEMT power devices is increasing. In industrial power systems represented by data centers, energy storage, automobiles and various industrial motors, the number, voltage and power level of power switches have increased significantly. The reliable control of GaN drive circuits at high frequency and high power is a difficult problem that GaN needs to focus on in large-scale applications of such systems.

[0003] GaN HEMT power devices can be divided into two types: enhancement type and depletion type. The process of depletion type GaN HEMT power devices is more mature and reliable, and has greater potential for large-scale manufacturing of power devices with a withstand voltage of more than 1,000 volts. At the same time, it turns on at zero voltage and turns off at negative voltage, and has a higher degree of freedom in designing the gate voltage swing range and threshold voltage, avoiding the problems of mis-turning on and excessive gate voltage in enhancement type devices.

[0004] At present, the driving of depletion-mode GaN HEMT power devices is mainly based on the series connection of depletion-mode GaN HEMT power devices and low-voltage Si MOSFET devices to form a cascode structure, and the driving schemes are divided into the following two types. The first driving scheme is to indirectly control the depletion-mode GaN HEMT power device by driving the Si MOSFET device. In this indirect driving scheme, the voltage at the connection point between the GaN HEMT power device and the Si MOSFET device is prone to overshoot and oscillation, which may cause the drain breakdown of the low-voltage MOSFET device, and the safety of the driving circuit is poor. The second driving scheme is that the depletion-mode GaN HEMT power device is directly controlled by zero voltage and negative voltage. It is necessary to convert the power supply voltage into a negative voltage for driving the low-voltage depletion-mode GaN HEMT power device through a negative voltage converter, and set a linear regulator to convert the power supply voltage into a voltage for driving the low-voltage Si MOSFET device. The circuit design corresponding to this negative voltage direct drive driving scheme is relatively complex, and the linear regulator has low efficiency. Summary of the invention

[0005] The embodiments of the present application provide a driving circuit and a switching power supply circuit of a GaN HEMT power device, so as to solve the problem that the driving circuit of the GaN HEMT power device in the prior art is relatively complicated.

[0006] The technical solutions provided by the embodiments of this application are as follows:

[0007] On the one hand, an embodiment of the present application provides a driving circuit for a GaN HEMT power device, comprising: a voltage conversion circuit consisting of a first switch module, an inductive energy storage module, at least one positive end capacitive energy storage module, at least one negative end capacitive energy storage module and a controller, at least one first driving module and at least one second driving module;

[0008] The first end of the first switch module is connected to an external power source, the second end of the first switch module is connected to the first end of the inductive energy storage module, the third end of the first switch module is connected to the first end of at least one negative voltage output branch, and the fourth end of the first switch module is connected to the controller; the second end of the inductive energy storage module is connected to the first end of at least one positive voltage output branch; the second end of each positive voltage output branch is connected to the positive voltage end of the corresponding first driving module; each positive end capacitive energy storage module is connected to the corresponding positive voltage output branch; the second end of each negative voltage output branch is connected to the negative voltage end of the corresponding second driving module; each negative end capacitive energy storage module is connected to the corresponding negative voltage output branch; the output end of each second driving module is connected to the gate of the corresponding external GaN HEMT power device, and the output end of each first driving module is connected to the gate of the corresponding external switch tube;

[0009] The first switch module is used to operate in a first state of connecting the inductive energy storage module to an external power source, or in a second state of connecting the inductive energy storage module to at least one negative pressure output branch under the control of the controller.

[0010] In a possible implementation, the first switch module includes: a first switch and a second switch;

[0011] The first end of the first switch is connected to an external power supply, the second end of the first switch is respectively connected to the first end of the second switch and the first end of the inductive energy storage module, and the second end of the second switch is connected to the first end of at least one negative voltage output branch; the control end of the first switch and the control end of the second switch are respectively connected to the controller.

[0012] In a possible implementation, the inductive energy storage module includes: an inductor;

[0013] The first end of the inductor is connected to the second end of the first switch module, and the second end of the inductor is connected to the first end of at least one positive voltage output branch.

[0014] In a possible implementation, the negative end capacitive energy storage module includes: at least one capacitor;

[0015] At least one capacitor forms a first capacitor branch, a first end of the first capacitor branch is connected to the corresponding negative voltage output branch, and a second end of the first capacitor branch is connected to the ground;

[0016] The positive end capacitive energy storage module includes: at least one capacitor;

[0017] At least one capacitor constitutes a second capacitor branch, a first end of the second capacitor branch is connected to the corresponding positive voltage output branch, and a second end of the second capacitor branch is connected to the ground.

[0018] In a possible implementation manner, the voltage conversion circuit further includes: a second switch module and a third switch module;

[0019] The first end of the second switch module is connected to the second end of the inductive energy storage module, and the second end of the second switch module is connected to the ground; the second switch module is used to connect or disconnect the connection between the inductive energy storage module and the ground;

[0020] The first end of the third switch module is connected to the second end of the inductive energy storage module, and the second end of the third switch module is connected to the first end of at least one positive pressure output branch; the third switch module is used to connect or disconnect the connection between the inductive energy storage module and the positive pressure output branch.

[0021] In a possible implementation, the third switch module includes: at least one third switch;

[0022] Each third switch is arranged on the corresponding positive pressure output branch, and the third switch is located between the first end of the positive pressure output branch and the connection point between the positive pressure output branch and the positive end capacitive energy storage module; the third switch is used to connect or disconnect the connection between the positive pressure output branch and the inductive energy storage module.

[0023] In a possible implementation, the driving circuit of the GaN HEMT power device further includes: at least one first voltage detection module;

[0024] The first end of the first voltage detection module is connected to the positive voltage end of the corresponding first driving module, and the second end of the first voltage detection module is connected to the controller; the first voltage detection module is used to detect the input voltage of the positive voltage end of the connected first driving module.

[0025] In a possible implementation manner, the controller is specifically configured to:

[0026] Receiving an input voltage of the positive voltage terminal of the first driving module detected by the first voltage detection module;

[0027] Determine whether the input voltage is less than the positive pressure preset value; if so, control the second switch module to cut off the connection between the inductive energy storage module and the ground, and control the third switch module to connect the connection between the inductive energy storage module and the positive pressure output branch; if not, control the second switch module to connect the connection between the inductive energy storage module and the ground, and control the third switch module to cut off the connection between the inductive energy storage module and the positive pressure output branch;

[0028] The first switch and the second switch are controlled to be turned on alternately according to a preset frequency and duty cycle.

[0029] In a possible implementation, the driving circuit of the GaN HEMT power device further includes: at least one second voltage detection module;

[0030] The first end of each second voltage detection module is connected to the negative voltage end of the corresponding second driving module, and the second end of each second voltage detection module is connected to the controller; the second voltage detection module is used to detect the input voltage of the negative voltage end of the connected second driving module.

[0031] On the other hand, an embodiment of the present application provides a switching power supply circuit, including: a driving circuit of the GaN HEMT power device provided in the embodiment of the present application, a power supply, at least one GaN HEMT power device and at least one switch tube;

[0032] The power supply end of the driving circuit of the GaN HEMT power device is connected to the power supply, the output end of the first driving module in the driving circuit of the GaN HEMT power device is connected to the gate of the corresponding switch tube, the output end of the second driving module in the driving circuit of the GaN HEMT power device is connected to the gate of the corresponding GaN HEMT power device, and the GaN HEMT power device and the corresponding switch tube are connected in series to form a common source and common gate structure.

[0033] The beneficial effects of the embodiments of the present application are as follows:

[0034] In the embodiment of the present application, based on the principle that the current direction of the inductive energy storage module cannot change suddenly and the voltage direction of the negative end capacitive energy storage module cannot change suddenly, by controlling the first switch module to switch between the first state or the second state, that is, connecting the inductive energy storage module to the external power supply, or connecting the inductive energy storage module to at least one negative voltage output branch, it is possible to simultaneously generate negative voltage and positive voltage through the same voltage conversion circuit, so as to simultaneously power the first driving module driving the external switch tube and the second driving module driving the GaN HEMT power device, without the need to additionally set up a linear regulator, simplifying the circuit setting, and improving the efficiency of the driving circuit.

[0035] Other features and advantages of the present application will be described in the subsequent description, and in part, will become apparent from the description, or will be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0037] Figure 1 It is a structural schematic diagram of an existing indirect drive solution in an embodiment of the present application;

[0038] Figure 2 It is a structural schematic diagram of the existing negative pressure direct drive solution in the embodiment of the present application;

[0039] Figure 3 This is a schematic diagram of a first circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0040] Figure 4 Schematic diagram of a second circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0041] Figure 5Schematic diagram of a third circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0042] Figure 6 Schematic diagram of a fourth circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0043] Figure 7 Schematic diagram of a fifth circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0044] Figure 8 A schematic diagram of a circuit structure of a voltage conversion circuit in an embodiment of the present application;

[0045] Fig. 9 This is a first working state diagram of the voltage conversion circuit in the embodiment of the present application;

[0046] Fig.10 Schematic diagram of the inductor current and switch state waveforms of the voltage conversion circuit in the embodiment of the present application;

[0047] Fig.11 This is a second working state diagram of the voltage conversion circuit in the embodiment of the present application;

[0048] Fig.12 Schematic diagram of a sixth circuit structure of a driving circuit of a GaN HEMT power device in an embodiment of the present application;

[0049] Fig.13 Schematic diagram of the seventh circuit structure of the driving circuit of the GaN HEMT power device in the embodiment of the present application;

[0050] Fig.14 Schematic diagram of the circuit structure of the switching power supply circuit in the embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and beneficial effects of this application clearer, the technical solution in the embodiment of this application will be clearly and completely described below in conjunction with the drawings in the embodiment of this application. Obviously, the described embodiment is only a part of the embodiment of this application, not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] It should be noted that the terms "first", "second", etc. mentioned in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0053] At present, the driving of depletion-mode GaN HEMT power devices is mainly based on the cascode structure formed by connecting depletion-mode GaN HEMT power devices in series with low-voltage Si MOSFET devices. The driving schemes are divided into the following two types. The first driving scheme is to indirectly drive the depletion-mode GaN HEMT power device by driving the Si MOSFET device. For details, please refer to Figure 1 As shown in the figure, the depletion-mode GaN HEMT power device is indirectly controlled by driving the Si MOSFET device. When the device is turned off, the drain voltage of the Si MOSFET device is limited by the threshold voltage of the GaN HEMT power device, and most of the voltage drop is borne by the GaN device. During high-speed switching, the device parasitic capacitance C OSS,GaN and C OSS,Si Mismatch effect, the junction voltage V between the depletion-mode GaN HEMT power device and the Si MOSFET device X Overshoot and oscillation are prone to occur, which may cause drain breakdown of low-voltage Si MOSFET devices and have poor safety. In addition, this indirect drive makes it impossible to directly control the dv / dt size of the switch node in the hard-switching power supply, which brings challenges to the electromagnetic interference reliability design of the power supply using depletion-mode GaN HEMT power devices. The second driving scheme is that the depletion-mode GaN HEMT power device is directly driven by zero voltage and negative voltage (V SS ) Control on and off, see Figure 2 As shown in the figure, the low-voltage Si MOSFET device is only turned off at startup to ensure safety, and it remains normally open during operation. Although this can avoid mismatch and reliability issues during the switching process, this traditional negative voltage direct drive solution requires a negative voltage converter to generate the total power supply V DD1 Converted to negative voltage V SS At the same time, a linear regulator is required to convert the total power supply V DD1 Converted to low voltage Si MOSFET drive supply voltage V DD2 This power supply system is complex in design and the linear regulator has low efficiency.

[0054] In order to solve the problem that the driving circuit of the GaN HEMT power device has poor reliability and a relatively complex circuit, the embodiment of the present application provides a driving circuit of the GaN HEMT power device, which is used to drive a switching device in a cascode structure formed by connecting at least one group of depletion-mode GaN HEMT power devices in series with a low-voltage Si MOSFET device, see Figure 3As shown, the driving circuit of the GaN HEMT power device provided in the embodiment of the present application at least includes: a voltage conversion circuit 160 composed of a first switch module 110, an inductive energy storage module 120, at least one positive end capacitive energy storage module 130, at least one negative end capacitive energy storage module 140 and a controller 150, at least one first driving module 170 and at least one second driving module 171;

[0055] The first end of the first switch module 110 is connected to an external power source, the second end of the first switch module 110 is connected to the first end of the inductive energy storage module 120, the third end of the first switch module 110 is connected to the first end of at least one negative voltage output branch, and the fourth end of the first switch module 110 is connected to the controller 150; the second end of the inductive energy storage module 120 is connected to the first end of at least one positive voltage output branch; the second end of each positive voltage output branch is connected to the positive voltage end of the corresponding first driving module 170; each positive end capacitive energy storage module 130 is connected to the corresponding positive voltage output branch; the second end of each negative voltage output branch is connected to the negative voltage end of the corresponding second driving module 171; each negative end capacitive energy storage module 140 is connected to the corresponding negative voltage output branch; the output end of each second driving module 171 is connected to the gate of the corresponding external GaN HEMT power device, and the output end of each first driving module 170 is connected to the gate of the corresponding external switch tube;

[0056] The first switch module 110 is used to operate in a first state of connecting the inductive energy storage module 120 to an external power source or in a second state of connecting the inductive energy storage module 120 to at least one negative pressure output branch under the control of the controller 150 .

[0057] exist Figure 3In the driving circuit of the GaN HEMT power device shown, the controller 150 can be a single-chip microcomputer, a DSP or other chips that can realize the control function. The first driving module 170 includes a driving chip for driving an external switch tube and other components used together with the driving chip, wherein the external switch tube refers to a low-voltage Si MOSFET device in a common source and common gate structure. The second driving module 171 includes a driving chip for driving an external depletion-type GaN HEMT power device and other components used together with the driving chip, wherein the GaN HEMT power device refers to a depletion-type GaN HEMT power device in a common source and common gate structure. The number of the positive end capacitive energy storage module 130, the positive voltage output branch, the first driving module 170 and the positive end capacitive energy storage module 130 is the same and corresponds one to one; the number of the negative end capacitive energy storage module 140, the negative voltage output branch, the second driving module 171 and the negative end capacitive energy storage module 140 is the same and corresponds one to one. Among them, each first driving module 170 drives a low-voltage Si MOSFET device, and each second driving module 171 drives a depletion-type GaN HEMT power device. The external power supply is VDD1, and its typical voltage range is 8V to 18V. The power supply of the first driving module is the positive voltage VDD2 output by the voltage conversion circuit, and the typical voltage range of VDD2 is 5V. The ground of the first driving module is the source voltage Source; the power supply of the second driving module is the source voltage Source, and the ground of the second driving module is the negative voltage VSS output by the voltage conversion circuit, and the typical voltage range of VSS is -10V to -20V.

[0058] The controller 150 can control the first switch module 110 to work in the first state or the second state. In the first state of the first switch module 110, the first switch module 110 connects the inductive energy storage module 120 with the external power supply, the inductive energy storage module 120 and the positive end capacitive energy storage module 130 are charged and stored by the external power supply, the negative end capacitive energy storage module 140 provides energy for the negative voltage end of the second driving module 171, and the external power supply provides energy for the positive voltage end of the first driving module 170; since the external power supply is positive voltage, the positive voltage end output voltage of the first driving module 170 is positive voltage at this time; in the second state of the first switch module 110, the first The switch module 110 connects the inductive energy storage module 120 to at least one negative voltage output branch, and the negative end capacitive energy storage module 140 charges and stores energy based on the energy released by the inductive energy storage module 120, and the inductive energy storage module 120 provides energy for the negative voltage end of the second driving module 171 in the circuit; the positive end capacitive energy storage module 130 provides energy for the positive voltage end of the first driving module 170; because the positive end capacitive energy storage module 130 charges and stores energy based on the energy released by the external power supply, the positive voltage end output voltage of the first driving module 170 is positive voltage. When the first state is switched to the second state, since the current direction of the inductive energy storage module 120 cannot change suddenly, the inductive energy storage module 120 can pull down the voltage of the second end of the negative voltage output branch to a negative voltage; when the second state is switched to, since the negative end capacitive energy storage module 140 is charged and stored based on the energy released by the inductive energy storage module 120 in the second state, and the voltage direction of the negative end capacitive energy storage module 140 cannot change suddenly, the negative end capacitive energy storage can also pull down the voltage of the second end of the negative voltage output branch to a negative voltage.

[0059] In this way, based on the principle that the current direction of the inductive energy storage module cannot change suddenly and the voltage direction of the negative end capacitive energy storage module cannot change suddenly, by controlling the first switch module to switch between the first state or the second state, that is, connecting the inductive energy storage module with the external power supply, or connecting the inductive energy storage module with at least one negative voltage output branch, it is possible to simultaneously generate negative voltage and positive voltage through the same voltage conversion circuit, so as to simultaneously power the first driving module driving the external switch tube and the second driving module driving the GaN HEMT power device, without the need to additionally set up a linear regulator, simplifying the circuit setting and improving the efficiency of the driving circuit, and there is no mismatch and reliability problem of the switching process in the traditional indirect driving scheme.

[0060] In a specific implementation, in the driving circuit 100 of the GaN HEMT power device of the present application, the first switch module 110 has a variety of structures to realize its function. Figure 4 As shown, the first switch module 110 may include: a first switch 111 and a second switch 112;

[0061] The first end of the first switch 111 is connected to an external power supply, the second end of the first switch 111 is respectively connected to the first end of the second switch 112 and the first end of the inductive energy storage module 120, and the second end of the second switch 112 is connected to the first end of at least one negative voltage output branch; the control end of the first switch 111 and the control end of the second switch 112 are respectively connected to the controller 150.

[0062] exist Figure 4 In the driving circuit of the GaN HEMT power device shown, the first switch is used to connect or disconnect the inductive energy storage module 120 from the external power supply under the control of the controller 150; the second switch 112 is used to connect or disconnect the inductive energy storage module 120 from at least one negative voltage output branch under the control of the controller 150. The first state of the first switch module 110 corresponds to the first switch being connected and the second switch 112 being disconnected; the second state of the first switch module 110 corresponds to the first switch being disconnected and the second switch 112 being connected.

[0063] It is worth mentioning that the number of second switches in the first switch module can also be multiple. Each second switch is arranged on the corresponding negative pressure output branch, and the second switch is located between the first end of the negative pressure output branch and the connection point between the negative pressure output branch and the negative end capacitive energy storage module; the second switch is used to connect or disconnect the connection between the negative pressure output branch and the inductive energy storage module. In this way, by setting a second switch on each negative pressure output branch, targeted control of each negative pressure output branch can be achieved, that is, the second switch on the negative pressure output branch that needs to output negative pressure at the second end can be controlled to be alternately turned on with the first switch to achieve targeted negative pressure output in the voltage conversion circuit.

[0064] In specific implementation, in the driving circuit 100 of the GaN HEMT power device of the present application, the inductive energy storage module 120 has a variety of structures to realize its function. For example Figure 5 As shown, the inductive energy storage module 120 may include: an inductor 121;

[0065] A first end of the inductor 121 is connected to a second end of the first switch module 110 , and a second end of the inductor 121 is connected to a first end of at least one positive voltage output branch.

[0066] exist Figure 5In the driving circuit of the GaN HEMT power device shown, the inductance of the inductor 121 needs to be determined according to the switching frequency in the voltage conversion circuit 160. The inductor 121 is used to charge and store energy through an external power supply when the first switch module 110 is in the first state. When the first switch module 110 is switched from the first state to the second state, since the current direction of the inductor 121 cannot change suddenly, the inductor 121 can pull the voltage of the second end of the negative voltage output branch down to a negative voltage, and at this time, the inductor releases energy to charge and store energy for the negative end capacitive energy storage module 140, so that when the first switch module 110 is in the first state, the voltage direction of the negative end capacitive energy storage module 140 cannot change suddenly, and the negative end capacitive energy storage can also pull the voltage of the second end of the negative voltage output branch down to a negative voltage.

[0067] In a specific implementation, in the driving circuit of the GaN HEMT power device of the present application, the negative end capacitive energy storage module and the positive end capacitive energy storage module have a variety of structures to realize their functions. The negative end capacitive energy storage module includes: at least one capacitor;

[0068] At least one capacitor forms a first capacitor branch, a first end of the first capacitor branch is connected to the corresponding negative voltage output branch, and a second end of the first capacitor branch is connected to the ground;

[0069] The positive end capacitive energy storage module includes: at least one capacitor;

[0070] At least one capacitor constitutes a second capacitor branch, a first end of the second capacitor branch is connected to the corresponding positive voltage output branch, and a second end of the second capacitor branch is connected to the ground.

[0071] Specifically, when the negative end capacitive energy storage module includes a capacitor, one end of the capacitor is connected to the corresponding negative voltage output branch, and the other end of the capacitor is connected to the ground; when the negative end capacitive energy storage module includes multiple capacitors, the multiple capacitors form a first capacitor branch in a series and / or parallel manner, the first end of the first capacitor branch is connected to the corresponding negative voltage output branch, and the second end of the first capacitor branch is connected to the ground. Similarly, when the positive end capacitive energy storage module includes a capacitor, one end of the capacitor is connected to the corresponding positive voltage output branch, and the other end of the capacitor is connected to the ground; when the positive end capacitive energy storage module 130 includes multiple capacitors, the multiple capacitors form a second capacitor branch in a series and / or parallel manner, the first end of the second capacitor branch is connected to the corresponding positive voltage output branch, and the second end of the second capacitor branch is connected to the ground. In addition, a controllable switch whose control end is connected to the controller 150 can also be provided in the first capacitor branch and the second capacitor branch, and the capacitance value of the first capacitor branch and the capacitance value of the second capacitor branch can be changed correspondingly by controlling the on and off of the controllable switch.

[0072] In one possible implementation, see Figure 6As shown, the voltage conversion circuit 160 of the driving circuit 100 of the GaN HEMT power device of the present application may also be provided with: a second switch module 180 and a third switch module 181;

[0073] The first end of the second switch module 180 is connected to the second end of the inductive energy storage module 120, and the second end of the second switch module 180 is connected to the ground; the second switch module 180 is used to connect or disconnect the connection between the inductive energy storage module 120 and the ground;

[0074] The first end of the third switch module 181 is connected to the second end of the inductive energy storage module 120, and the second end of the third switch module 181 is connected to the first end of at least one positive pressure output branch; the third switch module 181 is used to connect or disconnect the connection between the inductive energy storage module 120 and the positive pressure output branch.

[0075] exist Figure 6 In the driving circuit of the GaN HEMT power device shown, in order to avoid the mismatch and reliability problems of the low-voltage Si MOSFET device and the GaN HEMT power device during the switching process, the low-voltage Si MOSFET device is only turned off at startup to ensure safety, and it will remain in a normally open state during operation. The energy corresponding to the positive voltage required by the first driving module 170 is less than the energy corresponding to the negative voltage required by the second driving module 171. The second switch module 180 is set to connect the inductive energy storage module 120 with the ground, and the third switch module 181 is set to disconnect the inductive energy storage module 120 from the positive voltage output branch, and only the positive end capacitive energy storage module 130 is used to provide energy for the positive voltage end; when the positive voltage end cannot provide sufficient energy, the second switch module 180 is set to disconnect the inductive energy storage module 120 from the ground, and the third switch module 181 is set to connect the inductive energy storage module 120 with the positive voltage output branch, and the positive voltage end is provided with energy through an external power supply, and the positive end capacitive energy storage module 130 is charged through the external power supply, so that the positive end capacitive energy storage module 130 stores energy.

[0076] Specifically, the operating modes of the driving circuit of the GaN HEMT power device can be divided into a negative voltage mode and a positive and negative voltage mode.

[0077] In the negative pressure mode, the second switch module 180 connects the inductive energy storage module 120 to the ground, the third switch module 181 disconnects the inductive energy storage module 120 from the positive pressure output branch, and the first switch and the second switch 112 are alternately turned on. When the first switch is turned on and the second switch 112 is turned off, the negative end capacitive energy storage module 140 provides energy for the negative pressure end of the second driving module 171; when the first switch is turned off and the second switch 112 is turned on, the inductive energy storage module 120 provides energy for the negative pressure end of the second driving module 171 in the circuit; the positive end capacitive energy storage module 130 always provides energy for the positive pressure end of the first driving module 170.

[0078] In the positive and negative pressure mode, the second switch module 180 is set to disconnect the inductive energy storage module 120 from the ground, the third switch module 181 connects the inductive energy storage module 120 to the positive pressure output branch, and the first switch and the second switch 112 are alternately turned on. When the first switch is turned on and the second switch 112 is turned off, the negative end capacitive energy storage module 140 provides energy for the negative pressure end of the second driving module 171, and the external power supply provides energy for the positive pressure end of the first driving module 170; when the first switch is turned off and the second switch 112 is turned on, the inductive energy storage module 120 provides energy for the negative pressure end of the second driving module 171 in the circuit; the positive end capacitive energy storage module 130 provides energy for the positive pressure end of the first driving module 170.

[0079] In a specific implementation, in the driving circuit 100 of the GaN HEMT power device of the present application, the third switch module 181 has a variety of structures to realize its function. Figure 7 As shown, the third switch module 181 includes: at least one third switch 182;

[0080] Each third switch 182 is arranged on the corresponding positive pressure output branch, and the third switch 182 is located between the first end of the positive pressure output branch and the connection point between the positive pressure output branch and the positive end capacitive energy storage module 130; the third switch 182 is used to connect or disconnect the connection between the positive pressure output branch and the inductive energy storage module 120.

[0081] exist Figure 7 In the driving circuit of the GaN HEMT power device shown, by setting a third switch 182 on each positive voltage output branch, targeted control of each positive voltage output branch can be achieved, that is, the third switch 182 can be disconnected accordingly to provide energy to the corresponding positive voltage end only through the positive end capacitive energy storage module 130.

[0082] Next, Figure 8 Taking the voltage conversion circuit shown in the figure as an example, the working principle of the voltage conversion circuit in the driving circuit of the GaN HEMT power device is introduced in detail. Figure 8 In the embodiment, the first switch module includes a switch S1 and a switch S2, the inductive energy storage module includes an inductor L, and the driving circuit of the GaN HEMT power device includes a positive end capacitive energy storage module and a negative end capacitive energy storage module, wherein the positive end capacitive energy storage module includes a capacitor C1, and the negative end capacitive energy storage module includes a capacitor C2. The second switch module includes a switch S3, and the third switch module includes a switch S4. DD2 is the external power supply, V DD2 The port is a positive pressure output port, connected to the first drive module; V ss The port is a negative pressure output port and is connected to the second driving module.

[0083] When the driving circuit of the GaN HEMT power device works in the negative voltage mode, the working state of the voltage conversion circuit is as follows: Fig. 9 As shown, the inductor current and switch state waveforms in the voltage conversion circuit are as follows Fig.10 As shown, switch S3 is normally open, S4 is normally closed, and switches S1 and S2 are alternately turned on to control the inductor current, thereby providing energy for the negative voltage output port. The states of S1 and S2 being on are Φ1 and Φ2 respectively. It is worth mentioning that according to the voltage output, switches S1 and S2 can be controlled to be turned off to pass capacitor C1 to V DD2 The positive voltage is provided to the port through capacitor C2 to V ss The negative pressure is provided to the port, and the V DD2 The positive pressure provided by the port and V ss The port provides regulation of negative pressure.

[0084] When the driving circuit of the GaN HEMT power device works in the positive and negative voltage modes, the working state of the voltage conversion circuit is as follows: Fig.11 As shown, the inductor current and switch state waveforms in the voltage conversion circuit are as follows Fig.10 As shown, switch S4 is normally open, S3 is normally closed, and switches S1 and S2 are turned on alternately to control the inductor current. DD2 The port provides a positive voltage, V ss The port provides negative pressure. In this state, the states of S1 and S2 are Φ3 and Φ4 respectively.

[0085] In one possible implementation, see Fig.12 As shown, the driving circuit 100 of the GaN HEMT power device of the present application may further be provided with: at least one first voltage detection module 190;

[0086] The first end of the first voltage detection module 190 is connected to the positive voltage end of the corresponding first driving module 170, and the second end of the first voltage detection module 190 is connected to the controller 150; the first voltage detection module 190 is used to detect the input voltage of the positive voltage end of the connected first driving module 170.

[0087] In practical applications, the first voltage monitoring module may be composed of a voltage sensor, which may be a voltage divider resistor, a voltage transformer or a Hall voltage sensor. The controller 150 may determine the operating mode of the driving circuit 100 of the GaN HEMT power device according to the input voltage of the positive voltage terminal of the first driving module 170 detected by the first voltage detection module 190. Specifically, the controller 150 in the driving circuit 100 of the GaN HEMT power device is specifically used for:

[0088] Receiving an input voltage of the positive voltage end of the first driving module 170 detected by the first voltage detection module 190;

[0089] Determine whether the input voltage is less than the positive pressure preset value; if so, control the second switch module 180 to cut off the connection between the inductive energy storage module 120 and the ground, and control the third switch module 181 to connect the connection between the inductive energy storage module 120 and the positive pressure output branch; if not, control the second switch module 180 to connect the connection between the inductive energy storage module 120 and the ground, and control the third switch module 181 to cut off the connection between the inductive energy storage module 120 and the positive pressure output branch;

[0090] The first switch and the second switch 112 are controlled to be turned on alternately according to a preset frequency and duty cycle.

[0091] In practical applications, the input voltage of the positive voltage terminal of the first driving module 170 is the positive voltage output by the voltage conversion circuit 160. The positive voltage preset value is the voltage value required by the positive voltage terminal of the first driving module 170. When the input voltage of the positive voltage terminal of the first driving module 170 is less than the preset value, it means that the current output cannot meet the needs of the first driving module 170. The driving circuit 100 of the GaN HEMT power device should work in the positive and negative voltage mode, and the positive end capacitive energy storage module 130 is charged by the external power supply, and the positive voltage is provided to the first driving module 170 by the external power supply; when the input voltage of the positive voltage terminal of the first driving module 170 is greater than or equal to the preset value, it means that the current output can meet the needs of the first driving module 170. The driving circuit 100 of the GaN HEMT power device should work in the negative voltage mode, and the positive end capacitive energy storage module 130 provides the positive voltage to the first driving module 170.

[0092] In one possible implementation, see Fig.13 As shown, the driving circuit 100 of the GaN HEMT power device of the present application may further be provided with: at least one second voltage detection module 191;

[0093] The first end of each second voltage detection module 191 is connected to the negative voltage end of the corresponding second driving module 171, and the second end of each second voltage detection module 191 is connected to the controller 150; the second voltage detection module 191 is used to detect the input voltage of the negative voltage end of the connected second driving module 171.

[0094] In practical applications, the second voltage monitoring module can be composed of a voltage sensor, which can be a voltage divider resistor, a voltage transformer or a Hall voltage sensor. The controller 150 can determine the on-time of the first switch and the on-time of the second switch 112 in each cycle according to the negative voltage terminal voltage of the second driving module 171 detected by the second voltage detection module 191. Specifically, the controller 150 in the driving circuit 100 of the GaN HEMT power device is specifically used for:

[0095] Receiving an input voltage of the negative voltage terminal of the second driving module 171 detected by the second voltage detection module 191;

[0096] Determine whether the input voltage of the negative voltage end of the second driving module 171 is less than the negative voltage preset value; if so, increase the on-time of the first switch in each cycle and reduce the on-time of the second switch 112 in each cycle; if not, reduce the on-time of the first switch in each cycle and increase the on-time of the second switch 112 in each cycle.

[0097] The input voltage of the negative voltage terminal of the second driving module 171 is the negative voltage output by the voltage conversion circuit 160 . The negative voltage preset value is the voltage value required by the negative voltage terminal of the second driving module 171 .

[0098] In addition, based on the above embodiments, the present application also provides a switching power supply circuit, see Fig.14 As shown, the switching power supply circuit 200 provided in the embodiment of the present application at least includes: the driving circuit 100 of the GaN HEMT power device provided in the embodiment of the present application, a power supply 210 , at least one GaN HEMT power device 220 and at least one switch tube 230 .

[0099] The power supply end of the driving circuit 100 of the GaN HEMT power device is connected to the power supply 210, the output end of the first driving module in the driving circuit 100 of the GaN HEMT power device is connected to the gate of the corresponding switch tube 230, the output end of the second driving module in the driving circuit 100 of the GaN HEMT power device is connected to the gate of the corresponding GaN HEMT power device 220, and the GaN HEMT power device 220 and the corresponding switch tube 230 are connected in series to form a common source and common gate structure.

[0100] In practical applications, the positive voltage output terminal of the driving circuit of the GaN HEMT power device can not only provide positive voltage for the driving module of the switch tube, but also serve as a power supply for other power supply units that require positive voltage in the switching power supply circuit. The functions of the switching power supply circuit provided in the embodiment of the present application are detailed in the embodiment of the driving circuit of the GaN HEMT power device described above, which will not be repeated here.

[0101] It should be noted that, although several units or subunits of the device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided into multiple units to be embodied.

[0102] In addition, although the operations of the method of the present application are described in a specific order in the drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0103] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0104] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A driving circuit for a GaN HEMT power device, characterized in that: include: A voltage conversion circuit consisting of a first switch module, an inductive energy storage module, at least one positive end capacitive energy storage module, at least one negative end capacitive energy storage module and a controller, at least one first drive module and at least one second drive module; The first end of the first switch module is connected to an external power source, the second end of the first switch module is connected to the first end of the inductive energy storage module, the third end of the first switch module is connected to the first end of at least one negative voltage output branch, and the fourth end of the first switch module is connected to a controller; the second end of the inductive energy storage module is connected to the first end of at least one positive voltage output branch; the second end of each positive voltage output branch is connected to the positive voltage end of the corresponding first driving module; each positive end capacitive energy storage module is connected to the corresponding positive voltage output branch; the second end of each negative voltage output branch is connected to the negative voltage end of the corresponding second driving module; each negative end capacitive energy storage module is connected to the corresponding negative voltage output branch; the output end of each second driving module is connected to the gate of the corresponding external GaN HEMT power device, and the output end of each first driving module is connected to the gate of the corresponding external switch tube; The first switch module is used to operate in a first state of connecting the inductive energy storage module to an external power source, or in a second state of connecting the inductive energy storage module to at least one negative pressure output branch under the control of the controller.

2. The driving circuit of the GaN HEMT power device according to claim 1, characterized in that: The first switch module includes: a first switch and a second switch; The first end of the first switch is connected to an external power supply, the second end of the first switch is respectively connected to the first end of the second switch and the first end of the inductive energy storage module, the second end of the second switch is connected to the first end of at least one negative voltage output branch; the control end of the first switch and the control end of the second switch are respectively connected to the controller.

3. The driving circuit of the GaN HEMT power device according to claim 1, characterized in that: The inductive energy storage module includes: an inductor; The first end of the inductor is connected to the second end of the first switch module, and the second end of the inductor is connected to the first end of at least one positive voltage output branch.

4. The driving circuit of the GaN HEMT power device according to claim 1, characterized in that: The negative end capacitive energy storage module comprises: at least one capacitor; The at least one capacitor constitutes a first capacitor branch, a first end of the first capacitor branch is connected to the corresponding negative voltage output branch, and a second end of the first capacitor branch is connected to the ground; The positive end capacitive energy storage module comprises: at least one capacitor; The at least one capacitor constitutes a second capacitor branch, a first end of the second capacitor branch is connected to the corresponding positive voltage output branch, and a second end of the second capacitor branch is connected to the ground.

5. The driving circuit of the GaN HEMT power device according to any one of claims 1 to 4, characterized in that: The voltage conversion circuit further includes: a second switch module and a third switch module; The first end of the second switch module is connected to the second end of the inductive energy storage module, and the second end of the second switch module is connected to the ground; the second switch module is used to connect or disconnect the connection between the inductive energy storage module and the ground; The first end of the third switch module is connected to the second end of the inductive energy storage module, and the second end of the third switch module is connected to the first end of at least one positive pressure output branch; the third switch module is used to connect or disconnect the connection between the inductive energy storage module and the positive pressure output branch.

6. The driving circuit of the GaN HEMT power device according to claim 5, characterized in that: The third switch module includes: at least one third switch; Each of the third switches is arranged on the corresponding positive pressure output branch, and the third switch is located between the first end of the positive pressure output branch and the connection point between the positive pressure output branch and the positive end capacitive energy storage module; the third switch is used to connect or disconnect the connection between the positive pressure output branch and the inductive energy storage module.

7. The driving circuit of the GaN HEMT power device according to claim 5, characterized in that: Also includes: At least one first voltage detection module; The first end of the first voltage detection module is connected to the positive voltage end of the corresponding first driving module, and the second end of the first voltage detection module is connected to the controller; the first voltage detection module is used to detect the input voltage of the positive voltage end of the connected first driving module.

8. The driving circuit of the GaN HEMT power device according to claim 7, characterized in that: The controller is specifically used for: Receiving an input voltage of a positive voltage terminal of a first driving module detected by the first voltage detection module; Determine whether the input voltage is less than the positive pressure preset value; if so, control the second switch module to cut off the connection between the inductive energy storage module and the ground, and control the third switch module to connect the connection between the inductive energy storage module and the positive pressure output branch; if not, control the second switch module to connect the connection between the inductive energy storage module and the ground, and control the third switch module to cut off the connection between the inductive energy storage module and the positive pressure output branch; The first switch and the second switch are controlled to be turned on alternately according to a preset frequency and duty cycle.

9. The driving circuit of the GaN HEMT power device according to claim 7, characterized in that: Also includes: at least one second voltage detection module; The first end of each second voltage detection module is connected to the negative voltage end of the corresponding second driving module, and the second end of each second voltage detection module is connected to the controller; the second voltage detection module is used to detect the input voltage of the negative voltage end of the connected second driving module.

10. A switching power supply circuit, characterized in that: include: A driving circuit, a power supply, at least one GaN HEMT power device and at least one switch tube of a GaN HEMT power device according to any one of claims 1 to 9; The power supply end of the driving circuit of the GaN HEMT power device is connected to the power supply, the output end of the first driving module in the driving circuit of the GaN HEMT power device is connected to the gate of the corresponding switch tube, the output end of the second driving module in the driving circuit of the GaN HEMT power device is connected to the gate of the corresponding GaN HEMT power device, and the GaN HEMT power device and the corresponding switch tube are connected in series to form a common source and common gate structure.

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