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http://dx.doi.org/10.5762/KAIS.2020.21.10.1

LED driver IC design for BLU with current compensation and protection function  

Lee, Seung-Woo (P&L Semi)
Lee, Jung-Gi (Mechatronics, Korea Polytechnic University)
Kim, Sun-Yeob (Intelligent Information& Communication Namseoul University)
Publication Information
Journal of the Korea Academia-Industrial cooperation Society / v.21, no.10, 2020 , pp. 1-7 More about this Journal
Abstract
In recent years, as LED display systems are actively spread, study on effective control methods for an LED driver for driving the systems has been in progress. The most representative among them is the uniform brightness control method for the LED driver channel. In this paper, we propose an LED driver IC for BLU with current compensation and system protection functions to minimize channel luminance deviation. It is designed for current accuracy within ±3% between channels and a channel current of 150 mA. In order to satisfy the design specifications, the channel amplifier offset was canceled out by a chopping operation using a channel-driving PWM signal. Also, a pre-charge function was implemented to minimize the fast operation speed and luminance deviation between channels. LED error (open, short), switch TR short detection, and operating temperature protection circuits were designed to protect the IC and BLU systems. The proposed IC was fabricated using a Magnachip 0.35-um CMOS process and verified using Cadence and Synopsys' Design Tool. The fabricated LED driver IC has current accuracy within ±1.5% between channels and 150-mA channel output characteristics. The error detection circuits were verified by a test board.
Keywords
LED; Driver IC; Chopping; Current Compensation; BLU;
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