Patent ID: 8351173

Claim:
A power supply circuit, comprising: an energy-consuming component comprising an input terminal; an output over-voltage protection circuit connected to the input terminal of the energy-consuming component; and a feedback circuit connected to the output over-voltage protection circuit and the input terminal of the energy-consuming component, the feedback circuit capable of monitoring the voltage on the input terminal, comparing the voltage on the input terminal with a reference voltage, and turning off the output over-voltage protection circuit to cut off voltage provided to the input terminal of the energy-consuming component when the voltage on the input terminal is larger than the reference voltage; a control chipset and an input over-voltage protection circuit, wherein the input over-voltage protection circuit connects a supply voltage to the input terminal of the energy-consuming component; the control chipset defines a threshold voltage, the control chipset is capable of monitoring the supply voltage, and turning off the input over-voltage protection circuit to when the supply voltage is larger than the threshold voltage; the input over-voltage protection circuit comprises a first p-channel MOSFET connected in series between the supply voltage and the input terminal of the energy-consuming component; the control chipset comprises a first control end, the first control end is connected to a grid electrode of the first p-channel MOSFET, and capable of outputting a high level voltage signal to turn off the first p-channel MOSFET when the supply voltage is larger than the threshold voltage; and a drain electrode of the first p-channel MOSFET is connected to the supply voltage and a source electrode of the first p-channel MOSFET is connected to the input terminal of the energy-consuming component: the input over-voltage protection circuit further comprises a second p-channel MOSFET, the control chipset comprises a second control end, the second control end is connected to a grid electrode of the second p-channel MOSFET and capable of outputting a low level voltage signal to turn on the second p-channel MOSFET when the supply voltage is larger than the threshold voltage; and a drain electrode of the second p-channel MOSFET is connected to the input terminal of the energy-consuming component, and a source electrode of the second p-channel MOSFET is connected to ground; an inductor is connected between the drain electrode of the second p-channel MOSFET and the capacitor; a capacitor is connected between the inductor and ground, and a joint point of the inductor and the capacitor is connected to the input terminal of the energy-consuming component.