Patent ID: 8450947

Claim:
A method for driving a lamp of a backlight control circuit, the method comprising: providing a transformer, a control circuit, a first circuit, and a second circuit, the transformer comprising a primary winding and a secondary winding, an end of the secondary winding electrically connected to the lamp, the control circuit electrically connected with the primary winding of the transformer, the control circuit configured to cooperate with the transformer to provide an alternating current voltage to the lamp, the first circuit electrically connected with the other end of the secondary winding and comprising a first capacitor, the second circuit electrically connected with the other end of the secondary winding and comprising a first switching element, a reactance element and the first capacitor; the control circuit selectively switching off or on the first switching element; wherein when the control circuit switches off the first switching element, the secondary winding of the transformer outputs a startup AC voltage to the lamp, a first resonant circuit which comprises the lamp, the secondary winding of the transformer, and the first circuit is formed, the first resonant circuit having a first resonant frequency suitable to light the lamp; and when the control circuit switches on the first switching element, the secondary winding of the transformer outputs an operation AC voltage to the lamp, a second resonant circuit which comprises the lamp, the secondary winding of the transformer, the first and second circuits is formed, the second resonant circuit having a second resonant frequency suitable to keep the lamp lighted.