Design Of Dynamic Area Control Engine Of Led Backlight In LCD TV

Backlight module is the main power-consumption component in LCD TV. Traditional LCD TV adopts the brightness-constant backlight source which costs much energy even in displaying the dark image. This kind of power consumption problem becomes more serious in the large size application. Meanwhile, the contrast of the traditional LCD TV cannot be improved due to the light leakage characteristic of LC. Dynamic area control technique based on LED backlight can overcome these disadvantages to lower the power consumption and improve the contrast.The research on the theory and the progress of the dynamic area control technique shows that the dynamic backlight drive-signal-derived-algorithm is the core of this technique which determines the effect of the technique. The analysis and the comparison with several kind of the derived-algorithm indicate that the reduction of the backlight level (the cut down of the energy consumption) and the increase of the clipping distortion are mutual restrain. After the rigorous definition of clipping rate, a novel drive-signal-derived-algorithm based on clipping rate is proposed. Matlab simulation shows that this algorithm is better than the others for its better flexibility. It works well for different types of input image and keeps the clipping rate within the target range. It can also get the lowest area-drive-signal to meet the minimum power consumption and the highest contrast under a given clipping rate.The design of the overall architecture and the main modules (video-input module, backlight-control module, video-compensation module and video-output module) of the dynamic area control engine based on the novel algorithm is proposed, by using the Verilog-HDL language to describe. In the progress of design, the appropriate circuit structures are used to meet the modules'function and simplified circuits are applied to save the hardware resource. Finally, function simulations using Matlab, Quartus and ModelSim software show that all modules work well to meet the design function.