阅读说明：本技术 GaN功率管驱动电路、驱动方法及相应的电子装置 (GaN power tube driving circuit, driving method and corresponding electronic device ) 是由 张程龙 郭春明 李盛峰 于 2020-06-24 设计创作，主要内容包括：本发明提供了一种GaN功率管驱动电路、方法与电子装置,该驱动电路包括交流驱动单元与直流驱动单元；交流驱动单元用于根据第一控制信号输出驱动信号至GaN功率管的栅极,以驱动GaN功率管的开启与关闭；其中,驱动信号包括低电平驱动信号与高电平驱动信号；驱动信号与第一控制信号是同步变化的；直流驱动单元用于根据第二控制信号控制高电平驱动信号的电压处于第一电压,以及控制低电平驱动信号的电压处于第二电压。本驱动电路利用交流驱动单元实现GaN功率管的启闭,利用直流驱动单元控制GaN功率管开启和关闭时的驱动电压处于恒定的电压值,从而满足了GaN功率管低阈值电压及窄范围栅源工作电压的特性需求,能充分发挥其电气性能优势的同时提高可靠性。(The invention provides a GaN power tube driving circuit, a method and an electronic device, wherein the driving circuit comprises an alternating current driving unit and a direct current driving unit; the alternating current driving unit is used for outputting a driving signal to a grid electrode of the GaN power tube according to the first control signal so as to drive the GaN power tube to be opened and closed; the driving signals comprise low-level driving signals and high-level driving signals; the driving signal and the first control signal are synchronously changed; the direct current driving unit is used for controlling the voltage of the high-level driving signal to be at a first voltage according to the second control signal and controlling the voltage of the low-level driving signal to be at a second voltage. The driving circuit realizes the opening and closing of the GaN power tube by using the alternating current driving unit, and controls the driving voltage of the GaN power tube to be in a constant voltage value when the GaN power tube is opened and closed by using the direct current driving unit, so that the characteristic requirements of the GaN power tube on low threshold voltage and narrow-range grid source working voltage are met, the electrical performance advantages of the GaN power tube can be fully exerted, and the reliability is improved.)

1. A GaN power tube driving circuit is characterized by comprising an alternating current driving unit and a direct current driving unit;

the input side of the alternating current driving unit is used for accessing a first control signal, and the output side of the alternating current driving unit is connected with a grid electrode of the GaN power tube;

the input side of the direct current driving unit is used for accessing a second control signal, and the output side of the direct current driving unit is connected with the grid electrode of the GaN power tube; the second control signal is the same control signal as the first control signal, or: the second control signal is varied in response to variations in the first control signal;

the AC drive unit is configured to:

outputting a driving signal to a grid electrode of the GaN power tube according to the first control signal so as to drive the GaN power tube to be opened and closed; the driving signals comprise low-level driving signals and high-level driving signals; the drive signal is varied synchronously with the first control signal;

the direct current drive unit is used for:

and controlling the voltage of the high-level driving signal to be at a first voltage and controlling the voltage of the low-level driving signal to be at a second voltage in response to the change of the second control signal.

2. The GaN power tube driving circuit as claimed in claim 1, wherein the DC driving unit comprises a first voltage output module and a switch;

the output end of the first voltage output module is directly or indirectly connected with the grid electrode of the GaN power tube;

the first end of the change-over switch is connected with the output end of the first voltage output module, the second end of the change-over switch is directly or indirectly grounded, the control end of the change-over switch is connected with the second control signal, and the second control signal is used for controlling the on and off of the change-over switch so as to:

after the alternating current driving unit starts to output the high-level driving signal, the grid electrode of the GaN power tube is conducted with the first voltage output module, so that the high-level driving signal is at the first voltage; and

after the alternating current driving unit starts to output the low-level driving signal, the grid electrode of the GaN power tube is conducted with the ground, and the low-level driving signal is made to be at the second voltage.

3. The GaN power tube driving circuit of claim 2 wherein the second control signal is a signal obtained by inverting the first control signal.

4. The GaN power tube driving circuit of claim 2 wherein the dc driving unit further comprises a delay device;

the control end of the change-over switch is connected with the time delay device;

the delay device is used for delaying the second control signal and feeding the delayed second control signal back to the selector switch.

5. The GaN power tube driving circuit as claimed in claim 2, wherein the first voltage output module comprises a voltage follower, a non-inverting input terminal of the voltage follower is connected to a reference voltage, an inverting input terminal of the voltage follower is connected to an output terminal of the voltage follower, an output terminal of the voltage follower is connected to the gate of the GaN power tube and the first terminal of the switch, and the first voltage is matched with the reference voltage.

6. The GaN power tube driving circuit as claimed in any of claims 1 to 5, wherein the AC driving unit comprises a first switch tube, a second switch tube, an inverter and a coupling capacitor;

the first end of the first switch tube is connected with a power supply, the second end of the first switch tube is connected with the first end of the second switch tube, the second end of the second switch tube is grounded, the control end of the first switch tube is used for accessing the first control signal, the input side of the phase inverter is accessed with the first control signal, and the control end of the second switch tube is connected with the output side of the phase inverter;

the first end of the coupling capacitor is connected between the second end of the first switch tube and the first end of the second switch tube, and the second end of the coupling capacitor is connected with the grid electrode of the GaN power tube so as to output the driving signal.

7. The GaN power tube driving circuit as claimed in claim 6, wherein the AC driving unit further comprises an amplifier, the input side of the amplifier is connected to the first control signal, and the output side of the amplifier is connected to the control terminal of the first switch tube, so as to input the amplified first control signal to the control terminal of the first switch tube.

8. The GaN power tube driving circuit according to any of claims 1-5, further comprising a resistor, one end of the resistor is directly or indirectly connected to the gate of the GaN power tube, and the other end of the resistor is directly or indirectly connected to ground, wherein the on speed and/or the off speed of the GaN power tube is related to the resistance value of the resistor.

9. The GaN power tube driving circuit as claimed in claim 8, wherein a diode is further disposed between the resistor and the gate of the GaN power tube;

the anode of the diode is connected with the grid electrode of the GaN power tube, or: and the cathode of the diode is connected with the grid electrode of the GaN power tube.

10. The GaN power tube driving circuit as claimed in any of claims 1 to 5, further comprising a clamp protection unit connected to the grid of the GaN power tube for controlling the grid of the GaN power tube to be grounded when the voltage of the grid of the GaN power tube is higher than a safety threshold.

11. A driving method of a GaN power tube is characterized by comprising the following steps:

under the control of a first control signal, outputting a driving signal to a grid electrode of the GaN power tube through an alternating current driving unit so as to drive the GaN power tube to be opened and closed; the driving signals comprise low-level driving signals and high-level driving signals; the drive signal is varied synchronously with the first control signal;

controlling the voltage of the high-level driving signal to be at a first voltage and controlling the voltage of the low-level driving signal to be at a second voltage through a direct current driving unit according to a second control signal;

wherein the second control signal is the same control signal as the first control signal, or: the second control signal is varied in response to variations in the first control signal.

12. An electronic device, comprising the GaN power transistor driving circuit of any of claims 1 to 10, and a GaN power transistor driven by the GaN power transistor driving circuit.

13. The electronic device of claim 12, wherein the electronic device is a power converter.

Technical Field

The invention relates to the field of power tube driving, in particular to a GaN power tube driving circuit, a driving method and a corresponding electronic device.

Background

The GaN power transistor is a high electron mobility transistor with the electrical characteristics of small input capacitance, small on-resistance, low threshold voltage, narrow range gate-source operating voltage. The small input capacitance and the small on-resistance make it advantageous to increase the operating frequency of the switching power supply to reduce the size of the switching converter.

In the prior art, a conventional silicon power tube driving circuit is adopted to directly drive a GaN power tube.

However, the characteristics of the GaN power tube such as low threshold voltage and narrow-range gate-source operating voltage make the design reliability face higher challenges, and if the conventional silicon power tube driving circuit is used to directly drive the GaN power tube, accurate control of the driving voltage cannot be realized, so that the failure probability of the switching converter is greatly increased, the reliability of the GaN power tube is reduced, and the characteristic advantages of the GaN power tube cannot be fully exerted.

Therefore, how to accurately and effectively drive the GaN power transistor has become an urgent technical problem to be solved in the industry.

Disclosure of Invention

The invention provides a GaN power tube driving circuit, which aims to solve the problems that in the prior art, accurate control of a driving circuit cannot be realized, the reliability of GaN is reduced, and the advantages of electrical characteristics are difficult to give full play.

According to a first aspect of the present invention, a GaN power tube driving circuit is provided, which includes an ac driving unit and a dc driving unit;

the input side of the alternating current driving unit is used for accessing a first control signal, and the output side of the alternating current driving unit is connected with a grid electrode of the GaN power tube;

the input side of the direct current driving unit is used for accessing a second control signal, and the output side of the direct current driving unit is connected with the grid electrode of the GaN power tube; the second control signal is the same control signal as the first control signal, or: the second control signal is varied in response to variations in the first control signal;

the AC drive unit is configured to:

outputting a driving signal to a grid electrode of the GaN power tube according to the first control signal so as to drive the GaN power tube to be opened and closed; the driving signals comprise low-level driving signals and high-level driving signals; the drive signal is varied synchronously with the first control signal;

the direct current drive unit is used for:

controlling the voltage of the high-level driving signal to be at a first voltage and controlling the voltage of the low-level driving signal to be at a second voltage in response to a change of the second control signal.

Optionally, the dc driving unit includes a first voltage output module and a switch;

the output end of the first voltage output module is directly or indirectly connected with the grid electrode of the GaN power tube;

the first end of the change-over switch is connected with the output end of the first voltage output module, the second end of the change-over switch is directly or indirectly grounded, the control end of the change-over switch is connected with the second control signal, and the second control signal is used for controlling the on and off of the change-over switch so as to:

after the alternating current driving unit starts to output the high-level driving signal, the grid electrode of the GaN power tube is conducted with the first voltage output module, so that the high-level driving signal is at the first voltage; and after the alternating current driving unit starts to output the low-level driving signal, the grid electrode of the GaN power tube is conducted with the ground, so that the low-level driving signal is at the second voltage.

Optionally, the second control signal is a signal obtained by inverting the phase of the first control signal.

Optionally, the dc driving unit further includes a delay device; the control end of the change-over switch is connected with the time delay device; the delay device is used for delaying the second control signal and feeding the delayed second control signal back to the selector switch.

Optionally, the first voltage output module includes a voltage follower, a positive phase input end of the voltage follower is connected to a reference voltage, an negative phase input end of the voltage follower is connected to an output end of the voltage follower, an output end of the voltage follower is connected to a gate of the GaN power transistor and a first end of the switch, and the first voltage is matched with the reference voltage.

Optionally, the alternating current driving unit includes a first switching tube, a second switching tube, an inverter, and a coupling capacitor;

the first end of the first switch tube is connected with a power supply, the second end of the first switch tube is connected with the first end of the second switch tube, the second end of the second switch tube is grounded, the control end of the first switch tube is used for accessing the first control signal so as to be switched on and off under the control of the first control signal, the input side of the phase inverter is accessed with the first control signal, and the control end of the second switch tube is connected with the output side of the phase inverter so as to receive the inverted signal of the first control signal;

the first end of the coupling capacitor is connected between the second end of the first switch tube and the first end of the second switch tube, and the second end of the coupling capacitor is connected with the grid electrode of the GaN power tube so as to output the driving signal.

Optionally, the alternating current driving unit further includes an amplifier, an input side of the amplifier is connected to the first control signal, and an output side of the amplifier is connected to the control end of the first switching tube, so that the amplified first control signal is input to the control end of the first switching tube.

Optionally, the GaN power tube driving circuit further includes a resistor, one end of the resistor is directly or indirectly connected to the gate of the GaN power tube, and the other end of the resistor is directly or indirectly grounded, wherein the on speed and/or the off speed of the GaN power tube is related to the resistance of the resistor.

Optionally, a diode is further disposed between the resistor and the gate of the GaN power tube; the anode of the diode is connected with the grid electrode of the GaN power tube, or: and the cathode of the diode is connected with the grid electrode of the GaN power tube.

Optionally, the GaN power tube driving circuit further includes a clamp protection unit, where the clamp protection unit is connected to the gate of the GaN power tube to control the gate of the GaN power tube to be grounded when the voltage of the gate of the GaN power tube is higher than a safety threshold.

According to a second aspect of the present invention, there is provided a driving method of a GaN power tube, comprising:

under the control of a first control signal, outputting a driving signal to a grid electrode of the GaN power tube through an alternating current driving unit so as to drive the GaN power tube to be opened and closed; the driving signals comprise low-level driving signals and high-level driving signals; the drive signal is varied synchronously with the first control signal;

and controlling the voltage of the high-level driving signal to be at a first voltage and controlling the voltage of the low-level driving signal to be at a second voltage through a direct current driving unit according to a second control signal.

According to a third aspect of the present invention, there is provided an electronic device, comprising the GaN power tube driving circuit of any one of the above alternatives, and a GaN power tube driven by the GaN power tube driving circuit.

Optionally, the electronic device is a power converter.

The GaN power tube driving circuit provided by the invention can realize the opening and closing of the GaN power tube by utilizing the alternating current driving unit, and meanwhile, the direct current driving unit can control the voltage of the high-level driving signal to be in a first voltage, and the following steps are carried out: the voltage of the low-level driving signal is controlled to be at the second voltage, and then the voltage of the grid electrode of the GaN power tube can be accurately controlled, so that the driving voltage when the GaN power tube is started is at a constant voltage value, and the driving voltage when the GaN power tube is closed is also at a constant voltage value, therefore, the phenomenon that the grid electrode driving voltage of the GaN power tube in the prior art is unstable is avoided, the characteristic requirements of the GaN power tube on low threshold voltage and narrow-range grid source working voltage are met, and the reliability is improved while the electrical performance advantages are fully exerted.

Drawings

In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a first schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 2 is a second schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 3 is a third schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 4 is a fourth schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 5 is a fifth schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 6 is a sixth schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 7 is a seventh schematic diagram of a GaN power transistor driving circuit according to an embodiment of the invention;

FIG. 8 is a diagram illustrating an eighth exemplary GaN power transistor driving circuit;

FIG. 9 is a signal waveform diagram of a GaN power transistor driving circuit according to an embodiment of the invention.

Description of reference numerals:

1-GaN power tube driving circuit;

11-a direct current drive unit;

110-a first voltage output module;

12-an alternating current drive unit;

120-a first switch tube;

121-a second switch tube;

13-a clamp protection unit;

2-GaN power tube;

a1-amplifier;

a2-inverter;

A3-Voltage follower;

d1-zener diode;

d2-clamp diode;

d3-diode;

k-a diverter switch;

delay-delay devices;

C₀-a coupling capacitance;

ciss — input capacitance;

r-resistance.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, belong to the scope of protection of the present application.