Patent ID: 7557515

Claim:
A ballast control circuit for use with a fluorescent lamp comprising: a voltage controlled oscillator operable to provide an operating signal for the ballast control circuit, wherein a frequency of the operating signal depends only on an input voltage provided to the voltage controlled oscillator; and a driver circuit operable to provide a first driver signal via a first driver terminal and a second driver signal via a second driver terminal to drive a first switch and a second switch of a half bridge, respectively, wherein the first switch and the second switch are connected in series across a power source, such that a desired output voltage for powering the fluorescent lamp is provided at a node between the first switch and the second switch, wherein the first control signal and the second control signal control the first switch and the second switch to provide a desired duty cycle and dead time based on the frequency of the operating signal, and wherein the input voltage to the voltage controlled oscillator is provided at a power supply terminal providing a supply voltage to the ballast control circuit and is maintained within a desired range such that the frequency of the operating signal is maintained in a second desired range.