CN-122026877-A - Desaturation protection circuit, control method thereof and electronic equipment

Abstract

The application provides a desaturation protection circuit, a control method thereof and electronic equipment. The desaturation protection circuit is used for protecting a power switch device and comprises a first comparator, a desaturation detection capacitor and a second comparator, wherein the first comparator is configured to output a primary detection signal based on the voltage of a desaturation detection pin when the input of the control end of the power switch device is at a first level, the first end of the desaturation detection capacitor and the first end of the power switch device are both electrically connected with a desaturation detection capacitor node, the second end of the desaturation detection capacitor is electrically connected with the second end of the power switch device, the second comparator is configured to output a fault signal when the voltage of the desaturation detection capacitor node received through the first input end exceeds a reference voltage, and the fault signal is used for generating a desaturation protection trigger signal for turning off the power switch device. The embodiment of the application has stronger anti-interference capability and quicker response speed.

Inventors

• WEN JIAN
• CAI HONGLIANG
• SHAN LIANYU

Assignees

• 小米科技(武汉)有限公司
• 小米智能家电(武汉)有限公司
• 北京小米移动软件有限公司

Dates

Publication Date

20260512

Application Date

20260130

Claims (20)

1. 1. A desaturation protection circuit for protecting a power switching device, comprising: A first comparator having a first input terminal electrically connected to the desaturation detection pin and a second input terminal electrically connected to the control terminal of the power switching device, configured to output a primary detection signal based on the voltage of the desaturation detection pin when the input of the control terminal of the power switching device is at a first level; the first end of the desaturation detection capacitor and the first end of the power switch device are electrically connected with the desaturation detection capacitor node, and the second end of the desaturation detection capacitor is electrically connected with the second end of the power switch device; The first input end of the second comparator is electrically connected with the desaturation detection capacitor node, the input of the second input end is a reference voltage, the second comparator is configured to output a fault signal when the voltage of the desaturation detection capacitor node received through the first input end exceeds the reference voltage, and the fault signal is used for generating a desaturation protection trigger signal for turning off the power switch device.
2. 2. The desaturation protection circuit according to claim 1, wherein said first comparator comprises a first switching device, a second switching device, and a third switching device; The first input end and the second input end of the first comparator respectively comprise a control end of the first switching device and a control end of the second switching device; The first end of the first switching device and the first end of the second switching device are grounded through the third switching device; The output of the first comparator includes a second terminal of the second switching device.
3. 3. The desaturation protection circuit according to claim 2, wherein said first comparator further comprises a fourth switching device and a fifth switching device; The control end of the fourth switching device and the control end of the fifth switching device are electrically connected with the second end of the fourth switching device; the second end of the first switching device is electrically connected with the power supply voltage end through the fourth switching device; The second terminal of the second switching device is electrically connected to the power supply voltage terminal via the fifth switching device.
4. 4. The desaturation protection circuit according to claim 3, wherein said first comparator further comprises a sixth switching device and a seventh switching device; The input of the control end of the sixth switching device is an inverted control signal, the first end of the sixth switching device is electrically connected with the second end of the seventh switching device, the second end of the sixth switching device is electrically connected with the control end of the fourth switching device and the second end of the first switching device, the control end of the seventh switching device is electrically connected with the control end of the third switching device, and the first end of the seventh switching device is grounded.
5. 5. The desaturation protection circuit according to claim 4, wherein said first, second, third, sixth and seventh switching devices are all N-type field effect transistors; The fourth switching device and the fifth switching device are P-type field effect transistors.
6. 6. The desaturation protection circuit according to claim 1, wherein said second comparator comprises an eighth switching device, a ninth switching device, and a tenth switching device; The first input end and the second input end of the second comparator respectively comprise a control end of the eighth switching device and a control end of the ninth switching device; A first terminal of the eighth switching device and a first terminal of the ninth switching device are both electrically connected to the power supply voltage terminal via the tenth switching device; The output of the second comparator includes a second terminal of the ninth switching device.
7. 7. The desaturation protection circuit according to claim 6, wherein said second comparator further comprises an eleventh switching device and a twelfth switching device; The control end of the eleventh switching device and the control end of the twelfth switching device are electrically connected with the second end of the eleventh switching device; A second terminal of the eighth switching device is grounded via the eleventh switching device; A second terminal of the ninth switching device is grounded via the twelfth switching device.
8. 8. The desaturation protection circuit according to claim 7, wherein said eighth, ninth and tenth switching devices are P-type field effect transistors, and said eleventh and twelfth switching devices are N-type field effect transistors.
9. 9. The desaturation protection circuit according to claim 1, further comprising: The first end of the charging unit is electrically connected with the output end of the first comparator, the second end of the charging unit is electrically connected with the power supply voltage end, and the output end of the charging unit is electrically connected with the desaturation detection capacitor node; is configured to charge the desaturation detection capacitance when the primary detection signal is at a second level, such that the desaturation detection capacitance node is boosted.
10. 10. The desaturation protection circuit according to claim 9, wherein said charging unit comprises a thirteenth switching device and a fourteenth switching device, said thirteenth switching device having a conduction current capability greater than that of said fourteenth switching device; The input end of the charging unit comprises a control end of a thirteenth switching device, wherein the first end of the thirteenth switching device is grounded; the first end of the charging unit comprises a first end of a fourteenth switching device, and the input of the control end of the fourteenth switching device is a first bias voltage; The output terminal of the charging unit includes a second terminal of the thirteenth switching device and a second terminal of the fourteenth switching device electrically connected.
11. 11. The desaturation protection circuit according to claim 10, wherein said thirteenth switching device is an N-type field effect transistor and said fourteenth switching device is a P-type field effect transistor.
12. 12. The desaturation protection circuit according to claim 1, further comprising: And the first input end of the state latch is electrically connected with the output end of the second comparator, the output end is the desaturation detection pin and is configured to latch and output the voltage of the desaturation detection pin after the first input end receives the fault signal.
13. 13. The desaturation protection circuit according to claim 12, wherein said state latch comprises a fifteenth switching device, a sixteenth switching device, a seventeenth switching device and an output stage; a first input of the state latch comprises a control of the fifteenth switching device; The second end of the fifteenth switching device, the second end of the sixteenth switching device and the input end of the output stage are electrically connected to a first node; The seventeenth switching device is connected in parallel with the fifteenth switching device; the output of the state latch includes a control of the seventeenth switching device and an output of the output stage electrically connected.
14. 14. The desaturation protection circuit according to claim 13, wherein said output stage comprises an eighteenth switching device and a nineteenth switching device; The input end of the output stage comprises a control end of the eighteenth switching device and a control end of the nineteenth switching device which are electrically connected; the output end of the output stage comprises a second end of the eighteenth switching device and a second end of the nineteenth switching device which are electrically connected; A first terminal of the eighteenth switching device is electrically connected to the power supply voltage terminal, and a first terminal of the nineteenth switching device is grounded.
15. 15. The desaturation protection circuit according to claim 13, wherein said state latch further comprises a twentieth switching device; The input of the control end of the twentieth switching device is a reverse reset signal; A first end of the twentieth switching device is electrically connected to a second end of the fifteenth switching device; a second terminal of the twentieth switching device is electrically connected to a second terminal of the sixteenth switching device.
16. 16. The desaturation protection circuit according to claim 13, wherein said state latch further comprises a twenty-first switching device, The input of the control end of the twenty-first switching device is an inverted desaturation detection signal; a first end of the twenty-first switching device is electrically connected to the power supply voltage end; a second terminal of the twenty-first switching device is electrically connected to an input terminal of the charging unit.
17. 17. The desaturation protection circuit according to claim 13, wherein said fifteenth and seventeenth switching devices are N-type field effect transistors and said sixteenth switching device is a P-type field effect transistor.
18. 18. An electronic device comprising a power switching device and a desaturation protection circuit according to any one of claims 1-17; The power switch device is electrically connected with the output end of the desaturation protection circuit.
19. 19. A control method of a desaturation protection circuit, applied to the desaturation protection circuit according to any one of claims 1-17, comprising: when the first comparator detects that the input of the control end of the power switch device is at a first level, outputting a primary detection signal based on the voltage of the desaturation detection pin; The second comparator outputs a fault signal when the voltage of the desaturation detection capacitor node received through the first input end exceeds the reference voltage of the second input end, wherein the fault signal is used for generating a desaturation protection trigger signal for turning off the power switch device; the desaturation protection circuit includes the first comparator, the charging unit, and the second comparator.
20. 20. The method for controlling a desaturation protection circuit according to claim 19, further comprising: And when the primary detection signal is at a second level, the charging unit charges the desaturation detection capacitor, so that the desaturation detection capacitor node is boosted.

Description

Desaturation protection circuit, control method thereof and electronic equipment Technical Field The application relates to the technical field of electronic circuits, in particular to a desaturation protection circuit, a control method thereof and electronic equipment. Background Power switching devices (e.g., IGBTs, MOSFETs, etc.) are the core of modern power electronics systems, and their reliability directly determines the overall system performance and lifetime. However, these power switching devices are very susceptible to failure in operation due to faults such as over-current, short-circuit, etc., and the failure process is often a transient event on the order of microseconds (us). Therefore, fault detection and protection of the power switching device is critical. Desaturation (DESAT) detection technology has been developed as a mainstream active protection scheme. The basic principle is that whether the power switch device works in a safe saturation region is judged by detecting the voltage (Vce) or drain-source voltage (Vds) between the collector and the emitter of the power switch device, and if not, a fault signal is generated. However, the desaturation detection circuit in the related art has a contradiction between the anti-interference capability and the response speed, and has a strong anti-interference capability and a fast response speed. Disclosure of Invention Aiming at the defects of the existing mode, the application provides a desaturation protection circuit, a control method thereof and electronic equipment, which are used for solving the technical problems that the related technology is difficult to have stronger anti-interference capability and faster response speed. In a first aspect, an embodiment of the present application provides a desaturation protection circuit, including: a desaturation protection circuit for protecting a power switching device, comprising: A first comparator having a first input terminal electrically connected to the desaturation detection pin and a second input terminal electrically connected to the control terminal of the power switching device, configured to output a primary detection signal based on the voltage of the desaturation detection pin when the input of the control terminal of the power switching device is at a first level; the first end of the desaturation detection capacitor and the first end of the power switch device are electrically connected with the desaturation detection capacitor node, and the second end of the desaturation detection capacitor is electrically connected with the second end of the power switch device; The first input end of the second comparator is electrically connected with the desaturation detection capacitor node, the input of the second input end is a reference voltage, the second comparator is configured to output a fault signal when the voltage of the desaturation detection capacitor node received through the first input end exceeds the reference voltage, and the fault signal is used for generating a desaturation protection trigger signal for turning off the power switch device. Optionally, the first comparator includes a first switching device, a second switching device, and a third switching device; The first input end and the second input end of the first comparator respectively comprise a control end of the first switching device and a control end of the second switching device; The first end of the first switching device and the first end of the second switching device are grounded through the third switching device; The output of the first comparator includes a second terminal of the second switching device. Optionally, the first comparator further includes a fourth switching device and a fifth switching device; The control end of the fourth switching device and the control end of the fifth switching device are electrically connected with the second end of the fourth switching device; the second end of the first switching device is electrically connected with the power supply voltage end through the fourth switching device; The second terminal of the second switching device is electrically connected to the power supply voltage terminal via the fifth switching device. Optionally, the first comparator further includes a sixth switching device and a seventh switching device; The input of the control end of the sixth switching device is an inverted control signal, the first end of the sixth switching device is electrically connected with the second end of the seventh switching device, the second end of the sixth switching device is electrically connected with the control end of the fourth switching device and the second end of the first switching device, the control end of the seventh switching device is electrically connected with the control end of the third switching device, and the first end of the seventh switching device is grounded. Optionally, the first switching device, the second switching device, th