Patent ID: 8450940

Claim:
A gas-discharge lamp controller utilizing a novel preheating phase control mechanism, comprising: a supply voltage tracking reference voltages generator, biased between a supply voltage and a reference ground, for generating a first reference voltage which is proportional to said supply voltage; and a control unit, for generating a high threshold signal according to said first reference voltage and a saw-tooth signal, a peak value of said saw-tooth signal being proportional to said supply voltage, wherein said control unit has a preheating phase, said high threshold signal is coupled with said first reference voltage during said preheating phase, and the time duration of said preheating phase is set by a predetermined number of periods of said saw-tooth signal; wherein said supply voltage tracking reference voltages generator further generates a second reference voltage, which is proportional to said supply voltage and coupled to said control unit; and wherein said control unit further has an ignition phase after said preheating phase, said high threshold signal is coupled with said saw-tooth signal during said ignition phase, and the end of said ignition phase is determined when said saw-tooth signal reaches said second reference voltage.