CN-122026271-A - Overvoltage protection circuit, DC-DC converter, electric equipment and air conditioning unit

Abstract

The invention discloses an overvoltage protection circuit, a DC-DC converter, electric equipment and an air conditioning unit. The overvoltage protection circuit comprises a sampling module, a comparator, a reference voltage source, a switching tube and a control end, wherein the first end of the sampling module is connected with an input power supply of a DC-DC chip, the second end of the sampling module is grounded, the first input end of the comparator is connected with a third end of the sampling module, the input end of the reference voltage source is connected with a power supply of the overvoltage protection circuit, the output end of the reference voltage source is connected with a second input end of the comparator, the value of the reference voltage is adjustable, the input end of the switching tube is connected with an enabling pin of the DC-DC chip, the output end of the switching tube is grounded, and the control end of the switching tube is connected with the output end of the comparator and is used for being turned on or off according to signals output by the comparator. The invention can output variable reference voltage according to different DC-DC chip types, avoid protection delay or false triggering in advance, and improve the reliability of the overvoltage protection circuit.

Inventors

• GE YAN
• JIN GUOHUA
• YE TIEYING
• LIU QUANZHOU
• LI YUFA

Assignees

• 珠海格力电器股份有限公司

Dates

Publication Date

20260512

Application Date

20260311

Claims (14)

1. 1. An overvoltage protection circuit for use with a DC-DC chip, the overvoltage protection circuit comprising: the first end of the sampling module is connected with an input power supply of the DC-DC chip, and the second end of the sampling module is grounded; the first input end of the comparator is connected with the third end of the sampling module; The input end of the reference voltage source is connected with the power supply of the overvoltage protection circuit, and the output end of the reference voltage source is connected with the second input end of the comparator; And the input end of the switching tube is connected with the enabling pin of the DC-DC chip, the output end of the switching tube is grounded, and the control end of the switching tube is connected with the output end of the comparator and is used for being turned on or turned off according to the signal output by the comparator.
2. 2. The overvoltage protection circuit of claim 1, wherein the reference voltage source comprises: the input end of the adjustable voltage stabilizing source is connected with the power supply of the overvoltage protection circuit; The first voltage dividing resistor is connected with the output end of the adjustable voltage stabilizing source, the second voltage dividing resistor is grounded, a circuit between the first voltage dividing resistor and the second voltage dividing resistor is connected with the second input end of the comparator, and the resistance value of the first voltage dividing resistor and/or the second voltage dividing resistor is adjustable.
3. 3. The overvoltage protection circuit of claim 1, the overvoltage protection circuit is characterized by further comprising: the buffer is arranged between the sampling module and the comparator, the first input end of the buffer is connected with the third end of the sampling module, the second input end of the buffer is connected with the output end of the buffer, and the output end of the buffer is connected with the comparator.
4. 4. The overvoltage protection circuit of claim 1, the overvoltage protection circuit is characterized by further comprising: the first hysteresis resistor is connected with the output end of the comparator, and the second hysteresis resistor is grounded.
5. 5. The overvoltage protection circuit of claim 1, wherein the sampling module comprises: The third voltage dividing resistor is connected with an input power supply of the DC-DC chip, the fourth voltage dividing resistor is grounded, and a circuit between the third voltage dividing resistor and the fourth voltage dividing resistor is connected with the comparator.
6. 6. The overvoltage protection circuit of claim 1, wherein the enable pin of the DC-DC chip is further connected to an input power source of the DC-DC chip through a pull-up resistor.
7. 7. The overvoltage protection circuit of claim 6, the overvoltage protection circuit is characterized by further comprising: And the positive electrode of the unidirectional diode is connected with the pull-up resistor, and the negative electrode of the unidirectional diode is connected with the enabling pin of the DC-DC chip.
8. 8. The overvoltage protection circuit of claim 1, the overvoltage protection circuit is characterized by further comprising: and the first end of the decoupling capacitor is connected with the power supply of the overvoltage protection circuit, and the second end of the decoupling capacitor is grounded.
9. 9. The overvoltage protection circuit of claim 1, the overvoltage protection circuit is characterized by further comprising: The positive electrode of the LED indicator lamp is connected with the control end of the switch tube, and the negative electrode of the LED indicator lamp is grounded.
10. 10. The overvoltage protection circuit according to any one of claims 1 to 9, wherein the overvoltage protection circuit is packaged in an SMD package.
11. 11. A DC-DC converter comprising a DC-DC chip, characterized by further comprising an overvoltage protection circuit as claimed in any one of claims 1 to 9.
12. 12. A powered device comprising the DC-DC converter of claim 11.
13. 13. The powered device of claim 12, wherein the powered device is a compressor or a blower.
14. 14. An air conditioning assembly comprising the powered device of claim 12.

Description

Overvoltage protection circuit, DC-DC converter, electric equipment and air conditioning unit Technical Field The invention relates to the technical field of electronic power, in particular to an overvoltage protection circuit, a DC-DC converter, electric equipment and an air conditioning unit. Background DC-DC converters (DC-DC converters) are widely used in the field of power management, particularly in portable devices, industrial control modules and intelligent terminals, whose core function is to efficiently and stably convert an input voltage into a desired output voltage. However, in the practical application process, the input power may cause the input voltage to exceed the rated input voltage range of the DC-DC chip instantaneously or continuously due to external interference, abnormal power switching or user misconnection, etc., thereby causing breakdown of internal circuits of the chip, damage of the MOSFET, thermal runaway and even permanent failure. The common overvoltage protection scheme in the prior art mainly comprises the following three steps of firstly setting an external TVS (transient voltage suppression diode), namely, absorbing transient overvoltage, wherein the response speed is limited, and the continuous overvoltage cannot be handled, secondly setting a current limiting type protection circuit, cutting off a power supply by detecting an input current abnormality, and not having direct inhibition capability on an input voltage, thirdly setting a DC-DC chip with an overvoltage protection function, wherein the protection threshold value is fixed, the DC-DC chip cannot adapt to an application scene with a wide input voltage range, and the protection delay or false triggering risk exists when the voltage is suddenly changed. Aiming at the problems that the overvoltage protection threshold value of a DC-DC chip in the prior art is fixed, the application scene of a wide input voltage range cannot be adapted, and protection delay or false triggering risk exists when the voltage is suddenly changed, no effective solution is proposed at present. Disclosure of Invention The embodiment of the invention provides an overvoltage protection circuit, a DC-DC converter, electric equipment and an air conditioning unit, which are used for solving the problems that an overvoltage protection threshold value of a DC-DC chip in the prior art is fixed, the overvoltage protection circuit cannot adapt to an application scene with a wide input voltage range, and protection delay or false triggering risk exists when voltage is suddenly changed. In order to solve the above technical problems, the present invention provides an overvoltage protection circuit applied to a DC-DC chip, the overvoltage protection circuit comprising: the first end of the sampling module is connected with an input power supply of the DC-DC chip, and the second end of the sampling module is grounded; the first input end of the comparator is connected with the third end of the sampling module; The input end of the reference voltage source is connected with the power supply of the overvoltage protection circuit, and the output end of the reference voltage source is connected with the second input end of the comparator; And the input end of the switching tube is connected with the enabling pin of the DC-DC chip, the output end of the switching tube is grounded, and the control end of the switching tube is connected with the output end of the comparator and is used for being turned on or turned off according to the signal output by the comparator. Further, the reference voltage source includes: the input end of the adjustable voltage stabilizing source is connected with the power supply of the overvoltage protection circuit; The first voltage dividing resistor is connected with the output end of the adjustable voltage stabilizing source, the second voltage dividing resistor is grounded, a circuit between the first voltage dividing resistor and the second voltage dividing resistor is connected with the second input end of the comparator, and the resistance value of the first voltage dividing resistor and/or the second voltage dividing resistor is adjustable. Further, the overvoltage protection circuit further includes: the buffer is arranged between the sampling module and the comparator, the first input end of the buffer is connected with the third end of the sampling module, the second input end of the buffer is connected with the output end of the buffer, and the output end of the buffer is connected with the comparator. Further, the overvoltage protection circuit further includes: the first hysteresis resistor is connected with the output end of the comparator, and the second hysteresis resistor is grounded. Further, the sampling module includes: The third voltage dividing resistor is connected with an input power supply of the DC-DC chip, the fourth voltage dividing resistor is grounded, and a circuit between the third voltage dividing