Brightness adjustment circuit and display device

Abstract

An embodiment of the invention provides a brightness regulating circuit and a display device. The invention relates to the technical field of electronic and is used for improving the brightness regulation accuracy of an LED(Light-emitting diode) backlight module. The brightness regulating circuit comprises a control module, a driving module, a resistance module and an LED backlight module; the first end of the control module is connected with the resistance module, and the second end of the control module is connected with the driving module; the control end of the resistance module is connected with the control module, the first end of the resistance module is connected with the driving module, and the second end of the resistance module is connected with the ground; the first end of the driving module is connected with the control module, the second end of the driving module is connected with the LED backlight module, and the control end of the driving module is connected with the resistance module; the control module is used for outputting pulse width modulation waveform to the driving module, and used for controlling the resistance between the first and second end of the resistor module; the driving module is used for controlling the brightness of the LED backlight module according to the pulse width modulation waveform and the current value at the third end of the drive module. The embodiment of the invention are used for the brightness regulating circuit.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a brightness adjustment circuit and a display device. Background technique [0002] In the electronics industry, backlighting is a form of lighting that is often used on LCD (LiquidCrystal Display) to increase the illuminance in low light source environments and the brightness of displays and LCD screens. LED (Light Emitting Diode) is a solid-state semiconductor device that can directly convert electrical energy into light energy. In recent years, LED has gradually replaced the traditional CCFL (Cold Cathode Fluorescent Lamp) as the backlight source of LCD. [0003] In the use of LCD, the brightness of the LCD needs to be adjusted. In the prior art, the LED backlight is generally controlled by controlling the LED driver to adjust the brightness of the LCD. Pulse Width Modulation (PulseWidth Modulation, PWM for short) is usually used to adjust the brightness of the LCD. ) wa...

AI Technical Summary

Problems solved by technology

When the duty cycle of the PWM waveform reaches its upper limit, the LED driver 12 cannot further adjust the brightness of the LED backlight 13

Therefore, in the process of using the brightness adjustment system in the prior art, when the duty cycle of the PWM waveform input to the LED driver reaches its upper limit or lower limit, the LED driver cannot further adjust the brightness of the LED backlight, and the LED backlight The LCD where it is located cannot display content beyond the brightness adjustment range of the LED backlight, thus limiting the display performance of the LCD

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