Patent ID: 7432690

Claim:
A power supply for a load controller comprising: a rectifier circuit having a first input terminal connected to the hot terminal of an AC power source, a second input terminal connected to one of ground and neutral, and a third output terminal and a fourth output terminal connected to a DC power rail and a DC return rail respectively; a current limit circuit connected to said rectifier circuit comprising a current limiting device and a first capacitor, said current limiting device being configured to limit the corresponding one of leakage current to ground and leakage current to neutral, to a selected average level; and a regulator, said first capacitor being connected across said regulator, said regulator comprising a DC power input, a control input for receiving a pulse signal, a DC power output connected to said DC power rail and operable to provide power to a DC load when said DC load is connected with one load terminal thereof to said DC power rail and another load terminal thereof to said DC return rail, a main switch and an energy storage device connected between said DC power input and said DC power rail, a control switch, and a shunt regulator connected between said DC power rail and one of ground and said DC return rail for clamping said DC power rail to provide a shunt regulated output for said regulator, said control switch controlling operation of said main switch to be selectively opened and closed in accordance with said pulse signal to attain a selected duty cycle that determines a voltage on said first capacitor when current out of said first capacitor is limited by said selected level of said current limit circuit, said energy storage device providing power to said DC power rail when said main switch is open until said energy storage device has depleted energy stored therein.