Patent ID: 8358078

Claim:
A fluorescent lamp dimming circuit comprising: a full-wave rectifier operatively connected to an input to the fluorescent lamp dimming circuit for rectifying an input AC voltage into a rectified DC voltage; a power factor correction circuit operatively connected to the full-wave rectifier, the power factor correction circuit configured to produce a regulated DC buss voltage; a multi-function integrated circuit operatively connected to the power factor correction circuit comprising: a power factor control circuit for controlling the power factor correction circuit to produce the regulated DC buss voltage at a substantially constant voltage regardless of characteristics of the input AC voltage; a dimming control circuit configured to receive the regulated DC buss voltage and the input AC voltage and produce a dimmer driver signal, where a set of parameters of the dimmer driver signal vary depending on the input AC voltage, the input AC voltage being modified by a dimmer; and one or more switching devices operatively connected to the dimming control circuit, the one or more switching devices driven by the dimmer driver signal and inverting the regulated DC buss voltage to a primary voltage, wherein the one or more switching devices are configured to turn on simultaneously and to turn off simultaneously at increasing intervals, the intervals being a fraction of a duty cycle, until the duty cycle is reached; and a resonant tank circuit comprising a transformer and a capacitor, the resonant tank configured to receive the primary voltage.