LED backlight driving circuit and method for driving the LED backlight driving circuit

摘要

A light emitting diode (LED) backlight driving circuit includes a plurality of LED light bars, a power supply driving the LED light bars to light, and comparing units corresponding to the LED light bars one by one. A first input end of the comparing unit is coupled to a cathode end of the LED light bar, and a second input end of the comparing unit receives a first reference voltage. Each of the LED light bars is connected in series with a switching unit, an output end of the comparing unit is coupled to a statistic unit, an output end of the statistic unit is coupled to driving units corresponding to the switching units one by one and controlling the switching units to turn on/off. The statistic unit divides the LED light bars into two groups according to a logic state output by the comparing unit, and controls the driving unit to turn off one of two groups of LED light bars having a fewer number than the other group of the LED light bars.

主权项

1. A light emitting diode (LED) backlight driving circuit, comprising:
a plurality of LED light bars; a power supply that drives the LED light bars; and comparing units corresponding to the LED light bars one by one; wherein a first input end of each of the comparing units is coupled to a cathode end of the LED light bars, a second input end of each of the comparing units receives a first reference voltage; each of the LED light bars is connected in series with switching units, an output end of each of the comparing units is coupled to a statistic unit; an output end of the statistic unit is coupled to a plurality of driving units corresponding to the switching units one by one, and the driving units control the switching units to turn on/off; the statistic unit divides the LED light bars into two groups according to logic state output by each of the comparing units, and controls each of the driving units to turn off one of two groups of LED light bars having a fewer number than the other group of the LED light bars; wherein the statistic unit comprises a counting unit that sums an output voltage of each of the comparing units, and a logical decision unit coupled to the counting unit; when a value summing the output voltage of each of the comparing units by the counting unit exceeds a preset reference value, the logical decision unit controls each of the driving units to turn off one of two groups of LED light bars having a fewer number than the other group of the LED light bars.