An overvoltage protection circuit may include a reference voltage generator, a trigger circuit, and a clamping device. The reference voltage generator is for providing a reference voltage that is relatively constant during a powered EOS/ESD event. The trigger circuit is coupled to receive the reference voltage and a power supply voltage. The trigger circuit is for comparing the reference voltage to the power supply voltage. In response to detecting that the power supply voltage is above the reference voltage, the trigger circuit provides a trigger signal having a voltage proportional to a voltage level of the overvoltage event. The clamping device is coupled between a first power supply terminal and a second power supply terminal. The clamping device is for providing a current path between the first and second power supply terminals in response to the trigger signal.