Patent ID: 8598806

Claim:
A method for driving one or more cold-cathode fluorescent lamps, the method comprising: generating at least one drive signal associated with a signal frequency, the signal frequency being equal to a first predetermined frequency; receiving a current-sensing signal, the current-sensing signal being associated with a lamp current for the one or more cold-cathode fluorescent lamps in response to at least the first predetermined frequency; determining whether the current-sensing signal is larger than a first threshold in magnitude, the current-sensing signal being related to the first predetermined frequency; if the current-sensing signal related to the first predetermined frequency is determined to be larger than the first threshold in magnitude at anytime during a first period of time, changing the signal frequency from the first predetermined frequency to a second predetermined frequency, the second predetermined frequency being different from the first predetermined frequency; if the current-sensing signal related to the first predetermined frequency is determined to be smaller than the first threshold in magnitude throughout the first period of time, changing the signal frequency from the first predetermined frequency to a third predetermined frequency, the third predetermined frequency being different from the first predetermined frequency; generating at least the drive signal associated with the signal frequency, the signal frequency being equal to the third predetermined frequency; receiving the current-sensing signal, the current-sensing signal being associated with the lamp current in response to at least the third predetermined frequency; determining whether the current-sensing signal is larger than the first threshold in magnitude, the current-sensing signal being related to the third predetermined frequency; and if the current-sensing signal related to the third predetermined frequency is determined to be larger than the first threshold in magnitude at anytime during a second period of time, changing the signal frequency from the third predetermined frequency to the second predetermined frequency if the second predetermined frequency is different from the third predetermined frequency.