Patent ID: 7973760

Claim:
A backlight control circuit, comprising: a direct current (DC) power supply; a pulse width modulation integrated circuit (PWM IC) comprising a current sampling pin and an overvoltage protection pin, the PWM IC configured to stop working if any one of the current sampling pin and the overvoltage protection pin has a low voltage; a load circuit comprising a first light source, a second light source, and a rectifier and filter circuit, a low voltage terminal of the first light source being connected to the current sampling pin of the PWM IC via the rectifier and filter circuit, and a low voltage terminal of the second light source being connected to the overvoltage protection pin of the PWM IC via an input circuit, and configured to output a feedback signal corresponding to a working status of the second light source; wherein the input circuit comprises a switch diode and a voltage dividing diode, a cathode of the switch diode is configured to receive the feedback signal from the load circuit, and an anode of the switch diode is connected to the overvoltage protection pin of the PWM IC via the voltage dividing diode, when the feedback signal indicates a failure of the second light source, the switch diode is switched on and the voltage dividing diode is switched off such that a low voltage is applied to the overvoltage protection pin of the PWM IC and controls the PWM IC to stop working.