Patent ID: 7365499

Claim:
A continuous mode electronic ballast for operating a lamp comprising: a buck converter configured to generate a direct current (DC) bus voltage at a buck converter output; an inverter circuit operationally coupled to the buck converter configured to receive the generated DC voltage and convert the DC voltage into an alternating current (AC) voltage to drive the lamp; a power control circuit operationally coupled to the buck converter and configured to provide a control voltage signal to the buck converter so that the buck converter generates the output DC voltage and current of a predetermined value; the power control circuit including, a set point amplifier which includes: a first input connected to a line input voltage line, and a second input which is provided with a reference voltage, wherein the set point amplifier generates a voltage set point signal based on the line input voltage and reference voltage, the control voltage signal being generated based on the voltage set point signal; a crest factor reduction circuit operationally coupled to (a) the buck converter output to sense a rate of change in the generated DC bus voltage, and (b) the power control circuit to modify the control voltage signal based on the sensed rate of change in the DC bus voltage, wherein the modified control voltage signal forces the buck converter to generate the DC voltage, which when converted to the AC voltage, results in a current crest factor of lamp to be equal from about 1 to about 1.5.