Patent attributes
A circuit (200) for powering a high intensity discharge lamp (10) comprises first and second input terminals (202,204), first and second output terminal (206,208), first and second inverter switches (SW1,SW2), a transformer (240), first and second buck capacitors (CBUCK1,CBUCK2), first and second low-side capacitors (CLOWSIDE1,CLOWSIDE2), an ignitor (216), and a diode subcircuit (250,260). Transformer (240) includes a primary winding (242) and a secondary winding (244). During operation of circuit 200, primary winding (242) functions as a buck inductor, while secondary winding (244) operates in conjunction with diode subcircuit (250,260) to provide enhanced low frequency open circuit voltage (OCV) during the lamp starting phase and during steady-state powering of the lamp (10). Circuit (200) also allows for a lamp current having a non-zero average value. Circuit (200) is realizable with first and second low-side capacitors (CLOWSIDE1,CLOWSIDE2) having a relatively low capacitance value.
