Patent ID: 6072710
Filing Date: 2000-06-06
Classification: H05B,Y02B

Abstract:
A self-oscillating resonant converter for at least one discharge lamp which during normal operation exhibits lamp operating parameters of lamp voltage, lamp current and lamp power, wherein the converter comprises a half-bridge inverter including two field effect transistors and an output node between said transistors, a gate driving circuit for controlling said field effect transistors, and a linear core transformer having a load winding through which load current passes, the load winding having one end connected to the output node,characterized in that the transformer includes a control winding, andthe converter further comprises means for controlling the gate driving circuit during the normal operating state of the lamp to vary the oscillating frequency so as to maintain one of the lamp operating parameters constant, said means including a feedback and regulation circuit connected to and producing an AC control current in said control winding.