Patent ID: 8436664

Claim:
A circuit for implementing chip enable and power good control by a multi-functional pin of an integrated circuit, comprising: a current source connected to the multi-functional pin, supplying a current to the multi-functional pin; a first switch connected between the multi-functional pin and a ground terminal, switched by an enable signal; a second switch connected to the multi-functional pin; a current detector connected to the second switch, detecting a current of the second switch to determine a first signal; a first comparator connected to the multi-functional pin, comparing a voltage at the multi-functional pin with a first threshold to determine a second signal; a multiplexer connected to the current detector and the first comparator, selecting one of the first and second signals to enable or disable the integrated circuit; and a second comparator connected to the second switch and a feedback pin of the integrated circuit, generating a third signal to make the second switch be open circuit when a voltage at the feedback pin is higher than a second threshold.