Backlight control device and method for controlling a driving current of an LED
AssigneeAu Optronics Corporation
InventorsChih-Hsiang Yang, Fu-Cheng Wei
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Abstract
A backlight control device for controlling a driving current of an LED is disclosed. By controlling current outputs from current sources of a plurality of current output units, a display will be able to generate desirable backlight. Then by adjusting currents output by the plurality of current output units, brightness of a plurality of pixels can be dynamically adjusted. The brightness of pixels with higher gray levels can be increased while the brightness of pixels with lower gray levels can be decreased, thereby improving the contrast of image and saving power consumption.
Claims11
A backlight control device for controlling a driving current of a light-emitting diode, comprising:
- a pulse width modulation (PWM) control unit comprising:
- a register coupled to a shift register;
- and
- a control unit having an input node coupled to the register, and an output node;
- a current output unit coupled to the PWM control unit, comprising:
- a current source;
- and
- a transistor having a terminal coupled to the current source, and a gate coupled to the output node of the control unit of the PWM control unit;
- and
- the shift register, coupled to the PWM control unit, for storing control signals for controlling the PWM control unit;
- wherein the control unit regulates opening and closing of the gate of the transistor.
A method of driving a light-emitting diode (LED), comprising:
- storing a first control signal in a pulse width modulation (PWM) control unit;
- storing a second control signal in a current control unit;
- regulating voltage of a current source of a current output unit for driving the LED according to the second control signal;
- and
- regulating output current of the current output unit according to the first control signal.
Dependencies are inferred from the claim text.