The Transactions of the Korean Institute of Power Electronics (전력전자학회논문지)

The Korean Institute of Power Electronics (전력전자학회)
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Smart Dimming Control Algorithm for Reducing Power Consumption of LED TV Backlight

LED TV 백라이트 소비전력 저감을 위한 스마트 디밍 알고리즘 개발

  • Received : 2014.02.04
  • Accepted : 2014.04.15
  • Published : 2014.08.20
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Abstract

In this paper, the new smart dimming algorithm which is mixed with PWM and PAM control method is proposed for reducing the power consumption of LED TV Backlight. The proposed technique is using the curve characteristics of LED forward voltage and current which is proportionally changing LED forward voltage as changing LED forward current. Therefore, each PWM and PAM control method has different LED forward voltage and current in the same brightness condition. The PWM control method adjusts the brightness of LED TV Backlight by only varying the duty ratio of PWM and constantly sustaining the amplitude of LED forward current and voltage. So, the level of LED forward current and voltage in the PWM control method is relatively high and constant regardless of duty ratio of PWM. On the other hand, the PAM control method adjusts the brightness of LED TV Backlight by directly varying the level of LED forward current. So, the level of LED forward current and voltage in the PAM control method is lowered according to the brightness level. For the above-mentioned reason, the PAM control method has the advantage of reducing the total power consumption of LED TV Backlight at the brightness condition of below 100%, compared with PWM control method. By implementing this characteristic to LED driver circuit with control algorithm in MCU, the power consumption of LED TV Backlight can expect to be reduced. The effectiveness of the proposed method, new smart dimming algorithm, CPWAM(=Conditional Pulse Width Amplitude Modulation), has been verified by experimental results.

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References

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