LED backlight driver circuit

摘要

A light emitting diode (LED) backlight driver circuit includes an LED lightbar and a driver module of the LED lightbar. The driver module includes a backlight driver integrated chip (IC) regulating an output voltage of the driver module, and the backlight driver IC includes a first comparator correcting the output voltage of the driver module. The output end of each LED lightbar is coupled to an inverting input end of the first comparator, and a non-inverting input end of the first comparator is coupled to a protection module. The protection module includes a detection unit detecting an output current of the driver module. When the output current of the driver module detected by the detection unit is greater than a preset first current, the protection module outputs a first reference voltage to the non-inverting input end of the first comparator. When the output current of the driver module detected by the detection unit is lower than the preset first current, the protection module outputs a second reference voltage, which is lower than the first reference voltage, to the non-inverting input end of the first comparator.

主权项

1. A light emitting diode (LED) backlight driver circuit, comprising:
an LED lightbar; and a driver module driving the LED lightbar; wherein the driver module comprises a backlight driver integrated chip (IC) regulating an output voltage of the driver module, and the backlight driver IC comprises a first comparator correcting the output voltage of the driver module; an output end of each LED lightbar is coupled to an inverting input end of the first comparator, and a non-inverting input end of the first comparator is coupled to a protection module having a variable output voltage; wherein the protection module comprises a detection unit detecting an output current of the driver module; wherein when the output current of the driver module detected by the detection unit is greater than a preset first current, the protection module outputs a first reference voltage to the non-inverting input end of the first comparator, and when the output current of the driver module detected by the detection unit is lower than the preset first current, the protection module outputs a second reference voltage, which is lower than the first reference voltage, to the non-inverting input end of the first comparator, wherein the protection module comprises a second comparator, and the detection unit comprises a conversion assembly converting the detected current into a voltage, the conversion assembly is coupled to a non-inverting input end of the second comparator; an inverting input of the second comparator is coupled to a third reference voltage; the first reference voltage and the second reference voltage are separately coupled to two excitation ends of the second comparator; an output end of the second comparator is coupling to the non-inverting input of the first comparator; when the output current of the driver module detected by the detection unit is greater than the preset first current, the second comparator outputs the first reference voltage; when the output current of the driver module detected by the detection unit is lower than the preset first current, the second comparator outputs the second reference voltage.