Liquid crystal display, light-emitting diode (LED) backlight and driving method thereof

Abstract

The invention discloses a liquid crystal display, a light-emitting diode (LED) backlight and a driving method thereof. The LED backlight comprises a direct-current voltage input end, a booster circuit, an LED string and a constant-current driving circuit, wherein the direct-current voltage input end is used for inputting direct-current voltage; the booster circuit is used for boosting the direct-current voltage input through the direct-current voltage input end and outputting boosted direct-current voltage; the LED string comprises a plurality of series-connection LEDs and a first resistor and receives the boosted direct-current voltage from the booster circuit, and the direct-current voltage of the LED string normally emitting light is smaller than or equal to the boosted direct-current voltage output through the booster circuit; and the constant-current driving circuit is used for adjusting voltages at two ends of the first resistor so as to control current in the LED string. When the LEDs are driven to emit light, power consumption of a first metal oxide semiconductor (MOS) transistor in the constant-current driving circuit is lowered, so that power consumption of the constant-current driving circuit is reduced, the temperature is lowered, conversion efficiency of a whole driving circuit of the LED backlight is improved, and components in the constant-current driving circuit cannot be burnt out easily.

Description

technical field [0001] The invention relates to the field of liquid crystal display. More specifically, it relates to a liquid crystal display, a backlight module thereof, and an LED backlight source. Background technique [0002] With the continuous advancement of technology, the backlight technology of liquid crystal displays has been continuously developed. Traditional LCD backlights use cold cathode fluorescent lamps (CCFL). However, due to the shortcomings of CCFL backlight such as poor color reproduction ability, low luminous efficiency, high discharge voltage, poor discharge characteristics at low temperature, and long time for heating to reach a stable gray level, backlight technology using LED backlight has been developed. [0003] However, in the existing LED backlight drive circuit, due to the certain impedance of the MOS transistor in the constant current drive circuit, when driving the LED to emit light, the MOS transistor will generate power consumption, whic...

AI Technical Summary

Problems solved by technology

However, due to the disadvantages of CCFL backlight such as poor color reproduction ability, low luminous efficiency, high discharge voltage, poor discharge characteristics at low temperature, and long time for heating to reach a stable gray level, the backlight technology using LED backlight has been developed.

[0003] However, in the existing LED backlight drive circuit, due to the certain impedance of the MOS transistor in the constant current drive circuit, when driving the LED to emit light, the MOS transistor will generate power consumption, which will increase the power consumed by the constant current drive circuit. Then the temperature rises, resulting in a decrease in the conversion efficiency of the entire drive circuit of the LED backlight

Moreover, as the current of the LED increases, the power consumption generated by the MOS transistor increases, which makes the constant current drive circuit consume more power, and the temperature is higher, which is easy to damage the components in the constant current drive circuit.

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