US Patent 11387649 Operating circuit having ESD protection function

An operating circuit is provided. A first N-type transistor determines whether to create an open circuit between a core circuit and a ground terminal according to the voltage level of a specific node. An electrostatic discharge (ESD) protection circuit is coupled between an input/output pad and the core circuit to prevent an ESD current from passing through the core circuit. The ESD protection circuit includes a detection circuit and a releasing element. The detection circuit determines whether there is an ESD event at the input/output pad and generates a first detection signal according to the detection of the ESD event at the input/output pad. The releasing element provides a release path according to the first detection signal to release the ESD current. A control circuit controls the voltage level of the specific node according to the first detection signal.