CN-115694137-B - Diode peak current suppression circuit

CN115694137BCN 115694137 BCN115694137 BCN 115694137BCN-115694137-B

Abstract

The application relates to a diode peak current suppression circuit which comprises a first switch unit, a current sampling unit, an impedance switching module and a switch control module, wherein the first switch unit, the current sampling unit and the impedance switching module are connected in series, the series circuit is connected with a protected diode in parallel, a first output end of the switch control module is connected with a control end of the first switch unit and is used for adjusting current flowing through the first switch unit, and a second output end and a third output end of the switch control module are respectively connected with the impedance switching module and are used for adjusting impedance of the impedance switching module. According to the scheme, on one hand, the current flowing through the first switch unit is adjusted by adjusting the on time of the first switch unit, and on the other hand, the current in the loop is adjusted by adjusting the impedance value of the impedance switching module connected into the loop, so that the long-term work in a high-impedance loop can be avoided, and the power loss is greatly reduced.

Inventors

Xiao Zhedong
LV WENCHAO
Zhang Zee

Assignees

珠海格力电器股份有限公司

Dates

Publication Date: 20260505
Application Date: 20221121

Claims (10)

1. A diode peak current suppression circuit is used for suppressing peak current flowing through a protected diode and is characterized by comprising a first switch unit, a current sampling unit, an impedance switching module and a switch control module; The first switch unit, the current sampling unit, the impedance switching module and the capacitor are connected in series and then connected in parallel at two ends of the protected diode; the output end of the current sampling unit is connected with the input end of the switch control module; The first output end of the switch control module is connected with the control end of the first switch unit and is used for adjusting the current flowing through the first switch unit; the second output end and the third output end of the switch control module are respectively connected with the impedance switching module and are used for adjusting the impedance of the impedance switching module.
2. The diode peak current suppression circuit according to claim 1, wherein the switch control module includes a main control unit and a pulse width modulation unit; The first output end of the main control unit is connected with the input end of the pulse width modulation unit, and the output end of the pulse width modulation unit is connected with the control end of the first switch unit; The main control unit is used for outputting a control signal to the pulse width modulation unit, and the pulse width modulation unit is used for generating PWM waves with specified duty ratio according to the control signal.
3. The diode spike current suppression circuit of claim 2 wherein the master control unit is configured to output a control signal to cause the pulse width modulation unit to reduce the duty cycle of the generated PWM wave when the current in the loop is greater than a first threshold and less than a second threshold.
4. The diode peak current suppression circuit according to claim 2, wherein the impedance switching module includes a second switching unit, a third switching unit, and an impedance unit; the second switching unit and the impedance unit are connected in series, and the series line is connected in parallel with the third switching unit; The control end of the second switch unit is connected with the second output end of the main control unit, and the control end of the third switch unit is connected with the third output end of the main control unit.
5. The diode spike current suppression circuit of claim 4, wherein the master control unit comprises an MCU chip and a switching tube Q4; The second output end of the MCU chip is connected with the control end of the second switch unit; The second output end of the MCU chip is connected with the gate electrode of the switching tube Q4, and the source electrode of the switching tube Q4 is connected with the control end of the third switching unit.
6. The diode spike current suppression circuit of claim 5 wherein the impedance unit comprises a resistor R1, an inductance L1 and a diode D1; The resistor R1 is connected with the inductor L1 in series, and the diode D1 is connected with the inductor L1 in parallel.
7. The diode spike current suppression circuit of claim 5 wherein the second switching unit is a switching tube Q2 and the third switching unit is a switching tube Q3.
8. The diode spike current suppression circuit of claim 5 wherein the master control unit is configured to: when the current in the loop is smaller than the first current threshold value, the second switch unit is controlled to be turned off, and the third switch unit is controlled to be turned on; When the current in the loop is larger than the second current threshold value, the second switch unit is controlled to be turned on, and the third switch unit is controlled to be turned off.
9. The diode spike current suppression circuit according to any one of claims 1-4, wherein the current sampling unit comprises a sampling resistor R2 and an operational amplifier U1, two input terminals of the operational amplifier U1 are respectively connected with two ends of the sampling resistor R2, and an output terminal of the operational amplifier U1 is connected with an input terminal of the switch control module.
10. A power factor correction circuit comprising a diode spike current suppression circuit as claimed in any of claims 1-9.

Description

Diode peak current suppression circuit Technical Field The application relates to the technical field of electronics, in particular to a diode peak current suppression circuit. Background The air conditioner is widely used in the modern society, and the design of the related air conditioner circuit is also various. At present, the optimal design of air conditioner power supply is also increasing, wherein the PFC (Power Factor Correction ) circuit design is widely applied to air conditioner equipment. The PFC circuit has a great specific gravity in the design of the air conditioner, and the PFC circuit further includes a plurality of elements, so the PFC circuit is particularly important for the protection design of the elements in the PFC circuit, such as the protection design of the diode. In the related art, the design scheme of the diode peak current suppression circuit is generally realized by adding a resistor. While increasing the resistance can suppress the spike current to some extent, it can also result in increased power loss in the circuit. Disclosure of Invention In order to overcome the problem that the power loss in a circuit is increased when the peak current of a diode is restrained by adding a resistor in the related art at least to a certain extent, the application provides a peak current restraining circuit of the diode. According to a first aspect of an embodiment of the present application, there is provided a diode spike current suppression circuit for suppressing a spike current flowing through a protected diode, the circuit including a first switching unit, a current sampling unit, an impedance switching module, and a switch control module; The first switch unit, the current sampling unit and the impedance switching module are connected in series, and the series circuit is connected with the protected diode in parallel; the output end of the current sampling unit is connected with the input end of the switch control module; The first output end of the switch control module is connected with the control end of the first switch unit and is used for adjusting the current flowing through the first switch unit; the second output end and the third output end of the switch control module are respectively connected with the impedance switching module and are used for adjusting the impedance of the impedance switching module. Further, the switch control module comprises a main control unit and a pulse width modulation unit; The first output end of the main control unit is connected with the input end of the pulse width modulation unit, and the output end of the pulse width modulation unit is connected with the control end of the first switch unit; The main control unit is used for outputting a control signal to the pulse width modulation unit, and the pulse width modulation unit is used for generating PWM waves with specified duty ratio according to the control signal. Further, the main control unit is used for outputting a control signal to enable the pulse width modulation unit to reduce the duty ratio of the generated PWM waves when the current in the loop is larger than the first threshold value and smaller than the second threshold value. Further, the main control unit comprises an MCU chip and a switch tube Q4; the second output end of the MCU chip is connected with the control end of the second switch unit; The second output end of the MCU chip is connected with the gate electrode of the switching tube Q4, and the source electrode of the switching tube Q4 is connected with the control end of the third switching unit. Further, the impedance switching module comprises a second switch unit, a third switch unit and an impedance unit; the second switching unit and the impedance unit are connected in series, and the series line is connected in parallel with the third switching unit; The control end of the second switch unit is connected with the second output end of the main control unit, and the control end of the third switch unit is connected with the third output end of the main control unit. Further, the impedance unit comprises a resistor R1, an inductor L1 and a diode D1; The resistor R1 is connected with the inductor L1 in series, and the diode D1 is connected with the inductor L1 in parallel. Further, the second switching unit is a switching tube Q2, and the third switching unit is a switching tube Q3. Further, the main control unit is used for: when the current in the loop is smaller than the first current threshold value, the second switch unit is controlled to be turned off, and the third switch unit is controlled to be turned on; When the current in the loop is larger than the second current threshold value, the second switch unit is controlled to be turned on, and the third switch unit is controlled to be turned off. Further, the current sampling unit comprises a sampling resistor R2 and an operational amplifier U1, wherein two input ends of the operational amplifier U1 are res