Abstract: A controller includes a microcontroller and a control circuit. The control circuit includes circuitry structured to sense an alternating current (AC) from a current transformer coupled to the controller, convert the AC to direct current (rectified output DC), charge a capacitor to a first predetermined voltage level using the rectified output DC of the current transformer, and switch from a primary power supply for the microcontroller to a secondary power supply that includes the capacitor. The control circuit includes circuitry structured to cause the capacitor of the secondary power supply to provide power, at a second voltage level, to a clock coupled to the microcontroller.