Patent ID: 7948186

Claim:
A backlight control circuit comprising: an inverter configured to provide an alternating current voltage to a lamp; a pulse width modulation (PWM) circuit configured to provide a pulse control signal to the inverter; and a frequency setting circuit configured to regulate a frequency of the pulse control signal provided by the PWM circuit according to a temperature of the lamp; wherein the frequency setting circuit comprises a temperature sensor, a look-up table, an encoder, and an adjustable resistor, the temperature sensor is configured to sense the temperature of the lamp, the look-up table comprises a plurality of temperature values and a plurality of binary instructions corresponding to the temperature values, the encoder is configured to encode the binary instructions, and the frequency setting circuit is further configured to search the look-up table for a binary instruction corresponding to the temperature of the lamp, and output the binary instruction to the encoder to regulate a resistance of the adjustable resistor for regulating the frequency of the pulse control signal provided by the PWM circuit.