Patent ID: 7289308

Claim:
An overcurrent protection circuit for detecting an output current flowing through an output transistor, the overcurrent protection circuit comprising: an output voltage detection resistor for detecting an output voltage; a foldback overcurrent protection circuit for detecting an output current flowing through an output transistor and for controlling the output current flowing through the output transistor in accordance with the detected output current; a first logic generating circuit for receiving an overcurrent detection signal from the foldback overcurrent protection circuit corresponding to the detected output current; a second logic generating circuit for receiving a detection signal from the output voltage detection resistor corresponding to a decrease in the detected output voltage; an AND circuit for receiving and processing an overcurrent delay signal generated by the first logic generating circuit and a voltage detection signal generated by the second logic generating circuit; and a negative voltage generating circuit for receiving an output from the AND circuit and outputting a negative voltage to the foldback overcurrent protection circuit to control the flow of output current flowing through the output transistor.