Patent ID: 8599527
Filing Date: 2013-12-03
Classification: H02H

Abstract:
1. An overvoltage protection circuit, for providing an overvoltage protection when an input voltage exceeds a rated voltage tolerable of an internal circuit unit of a portable electronic device, comprising: an input unit, for receiving the input voltage; an output unit, for connecting the portable electronic device; a voltage limiting unit, coupled to the input unit for receiving the input voltage and restrictively outputting a reference voltage; a voltage dividing module, coupled to the input unit, for receiving the input voltage, and dividing the input voltage to produce a partial voltage; a comparing module, coupled to the voltage limiting unit and the voltage dividing module, for comparing the reference voltage with the partial voltage, and generating a switch signal according to a comparison result; and a switch unit, coupled to the input unit, the output unit and the comparing module, for receiving the switch signal and the input voltage, and the switch signal being used for controlling the input voltage to be outputted to the output unit through the switch unit; wherein the comparing module further comprises a first input terminal, a second input terminal, a first control unit and a second control unit, and the first control unit is coupled to the first input terminal, the second input terminal and the second control unit, and the first input terminal is coupled to the voltage limiting unit, and the second input terminal is coupled to the voltage dividing module for inputting the reference voltage and the partial voltage to the first control unit and generating a control signal and outputting the control signal to the second control unit to form the switch signal after the reference voltage and the partial voltage are compared.