Patent ID: 8767365
Filing Date: 2014-07-01
Classification: H02H

Abstract:
1. A protection circuit for a device powered by an output power supply, the protection circuit comprising: an electronic switch; a comparator comprising a positive input connected to a first power supply, a negative input connected to the output power supply, and an output connected to a first terminal of the electronic switch through a first resistor; wherein a second terminal of the electronic switch is connected to the device, a third terminal of the electronic switch is connected to the negative input; a diode; and a processor, wherein an anode of the diode is connected to the processor, a cathode of the diode is connected to the output of the comparator, the anode of the diode is further connected to a second power supply through a second resistor, the diode outputs an overvoltage signal to the processor when the voltage on the positive input is greater than the voltage on the negative input of the comparator; and wherein when a voltage on the positive input is greater than a voltage on the negative input of the comparator, the comparator outputs a high level signal to turn on the electronic switch, thus the output power supply outputs power to the device; when the voltage on the positive input is less than the voltage on the negative input of the comparator, the comparator outputs a low level signal to turn off the electronic switch, the output power supply does not output power to the device.