Patent ID: 8237419

Claim:
A thermally efficient protective circuit, for a circuit protection device comprising: a connection to a source of AC power; a connection to a rectifier for converting the AC power to DC; a power supply capacitor for storing a DC voltage; a voltage regulator selectively receiving power from one of the rectifier or the power supply capacitor, the voltage regulator supplying regulated power to all components of the protective circuit; a power supply switch electrically connected in series between the rectifier and the power supply capacitor for selectively providing power from the rectifier to the power supply capacitor and the voltage regulator, and; a microprocessor powered by the regulated power and controlling all functions of the protective circuit including dynamic control of the power supply switch with respect to a lowest point of the AC power source voltage waveform wherein the microprocessor initiates closing of the power supply switch at a point near the lowest point on the AC source voltage waveform that will provide the determined minimum time for charging the power supply capacitor when the power supply switch remains closed symmetrically about a zero crossing on the AC source voltage waveform.