Selecting external or internal mode settings from a single pin

Abstract

A control circuit for controlling a power module is provided. The power module drives a processing circuit. The control circuit includes a first resistor, a second resistor, a trigger circuit, and a switch circuit. The first resistor is coupled between a first reference voltage and a setting input terminal. The second resistor is coupled between a second reference voltage and the setting input terminal. The trigger circuit provides a switching signal in response to an operating signal. The switch circuit transmits a control signal to the setting input terminal in response to a first voltage level, and stops transmitting the control signal in response to a second voltage level. The power module executes one of a first power supply mode and a second power supply mode in response to a voltage value. When the control signal is not received, the power module executes a third power supply mode.