Patent ID: 7902765

Claim:
A circuit system for driving a high-intensity discharging lamp, comprising: a boosting circuit, including a first transformer and a first switch, in which the first transformer has a primary winding for receiving an input power and a secondary winding for producing a boosting DC voltage, and the first switch is connected to the first transformer to control turning-on and turning-off of the first transformer; an ignition coil circuit, connected to the boosting circuit for converting the boosting DC voltage into a switching AC voltage to drive a load; and a clamp circuit, connected to the boosting circuit and the ignition coil circuit for directing energy, reflected from the secondary winding of the first transformer to the primary winding of the first transformer, to the secondary winding of the first transformer as the first switch is turned off, wherein the clamp circuit is a current gain circuit which is comprised of a first diode, a second diode and a first capacitor; the positive terminal of the first diode is connected to the first switch and the primary of the first transformer; the negative terminal of the first diode is connected to the positive terminal of the first capacitor and the negative terminal of the first capacitor is connected to a low potential; the positive terminal of the second diode is connected to the negative terminal of the first diode and the positive terminal of the first capacitor, and the negative terminal of the second diode is connected to the secondary of the first transformer.