A circuit breaker includes separable contacts, an operating mechanism structured to open and close the separable contacts, a current sensor structured to sense current flowing through the separable contacts, a microprocessor cooperating with the sensor and the operating mechanism to trip open the separable contacts, and a power supply structured to at least power the microprocessor. The microprocessor includes a configurable clock and a routine structured to reduce current consumption from the power supply through modulation of the configurable clock.