LED backlight driving circuit, LCD device, and method for driving the LED backlight driving circuit

摘要

A light emitting diode (LED) backlight driving circuit includes a power module, a constant current driving module, and an LED light bar coupled to the power module. A light-bar-voltage collecting module is coupled to an output end of the LED light bar and outputs a first comparison voltage. A power-voltage collecting module is coupled to an output end of the power module and outputs a second comparison voltage. The constant current driving module includes a switching unit and a control unit. The control unit adjusts an output voltage of the power module. A preset reference voltage is sent to the switching unit. When an absolute value of a difference between a preset reference voltage and the first comparison voltage exceeds a preset range of a voltage, the switching unit outputs the first comparison voltage to the control unit.

主权项

1. A light emitting diode (LED) backlight driving circuit, comprising:
a power module; a constant current driving module; an LED light bar coupled to the power module; a power-voltage collecting module coupled to an output end of the power module; and a light-bar-voltage collecting module coupled to an output end of the LED light bar; wherein the light-bar-voltage collecting module outputs a first comparison voltage, and the power-voltage collecting module outputs a second comparison voltage; the constant current driving module comprises a switching unit and a control unit coupled to the switching unit; the control unit adjusts an output voltage of the power module, the first comparison voltage and the second comparison voltage are sent to the switching unit, and a preset reference voltage is sent to the switching unit; and the switching unit comprises a comparing assembly, the comparing assembly compares the first comparison voltage with the preset reference voltage and an absolute value of a difference between the preset reference voltage and the first comparison voltage exceeds a preset range of a voltage, the switching unit outputs the first comparison voltage to the control unit; when the absolute value of the difference between the preset reference voltage and the first comparison voltage is within the preset range of the voltage, the switching unit outputs the second comparison voltage to the control unit.