Patent ID: 8497636

Claim:
A circuit for powering at least one light source, comprising: a rectifier having AC input terminals to receive AC input power and first and second DC output terminals to provide rectified DC power; a boost converter receiving the rectified DC power from the rectifier and providing a first DC output, the boost converter comprising: an inductance having a first terminal coupled with the first DC output terminal of the rectifier and a second terminal, a diode with an anode coupled with the second terminal of the inductance and a cathode, a bus capacitance with a first terminal coupled with the cathode of the diode and a second terminal coupled to a circuit ground node, and a triac compatibility circuit, comprising: a switching device coupled between the anode of the diode and the circuit ground, and including a control terminal, the switching device operative to selectively electrically couple the anode of the diode and the circuit ground or to disconnect the anode of the diode from the circuit ground according to a signal received at the control terminal, and an auto switching driver circuit including a sense resistor coupled between the circuit round and the second DC output terminal of the rectifier to sense current flowing in the switching device, the auto switching driver circuit operative to provide a variable frequency alternating switching control signal to the control terminal of the switching device based at least in part on a voltage across the sense resistor to provide a regulated current flow in the boost converter independent of phase-cutting at the AC input terminals of the rectifier; and a DC to DC converter circuit with DC input terminals coupled with the first and second terminals of the bus capacitance, and DC output terminals providing a second DC output to directly or indirectly provide power to at least one light source.