Patent ID: 8368320

Claim:
A method for controlling a driving circuit of a cold cathode fluorescent lamp (CCFL), comprising: sensing a lamp current or a lamp voltage of the CCFL to provide a feedback signal; detecting an operation status of the CCFL and providing a status signal; processing the feedback signal and the status signal to generate a control signal; comparing the control signal with a frequency sweeping threshold to generate a comparison signal; according to the comparison signal, selectively applying the control signal to regulate a duty ratio or a frequency of a switching control signal that controls the driving circuit; wherein the status signal comprises a first logic state representing that the CCFL is in normal operation and a second logic state representing that the CCFL is in a fault condition or in ignition; and wherein the control signal is regulated by the feedback signal and is clamped between a minimum control value and a maximum control value when the status signal is in the first logic state, and is increased to a predetermined final control value when the status signal is in the second logic state.