Patent ID: 7859812

Claim:
A power IC with an over-current protection, for receiving an input voltage and converting the input voltage into an output voltage to a load, comprising: a power transistor for providing an output current to the load; a feedback circuit for detecting the output voltage to generate a feedback signal; an output control unit for receiving the feedback signal and calculating the feedback signal and a reference voltage source to generate a voltage control signal to control the power transistor; and an over-current protection circuit having a constant current limit threshold and a fold-back current limit threshold for controlling the power transistor to adjust the output voltage and the output current; wherein, when the output current is larger than the constant current limit threshold, the over-current protection circuit clamps the output current to a constant current value to lower the output voltage to a rated value, and when the output current is larger than the fold-back current limit threshold, the over-current protection circuit limits the output current to a low current value to descend the output voltage to zero.