Analysis and Suppression of Overcurrent in Boost LED Drivers

作者：Hsieh Yuan Ta^*; Juang Ying Zong

来源：Journal of Display Technology, 2013, 9(5): 388-395.

DOI：10.1109/JDT.2012.2226561

• Current limit
• integrated circuit
• LED driver
• LED lifespan
• LED overcurrent suppression
• soft start

Light-emitting diodes (LEDs) are the major back-lighting source used in liquid crystal displays and dimming the LEDs is a common approach to increase the contrast ratio or save power. Pulse-width modulation (PWM) is more popular than analog methods of dimming, because it produces a less pronounced shift in chromaticity. However, in PWM dimming mode, overcurrent can shorten the lifespan of the LEDs. This paper proposes a technique to overcome the drawbacks inherent in conventional approaches to the suppression of overcurrent in LED devices. The design was implemented using the TSMC 0.25-mu m 60-V bipolar-CMOS-DMOS process, resulting in a chip area of 2.2 mm(2). A comparison with two commercial chips demonstrates the effectiveness of the proposed design in the suppression of LED overcurrent and the subsequent extension of the lifespan.

• 出版日期2013-5