US Patent 7279854 Charge pump interface circuit

A ballast circuit including a charge pump interface circuit is disclosed to provide a method of isolating a switch from a power line used to power a ballast for supplying electrical power to a lamp. In addition, the charge pump interface circuit provides a method to control a discrete dimming ballast circuit which includes one or more inverters. The charge pump interface circuit offers cost advantages because no relays are necessary for isolation of the switch from the lamp electrical power and the dimming ballast circuit can be installed where existing lamps are currently mounted, without the need to add additional wiring.