A dual-path, current-sensing resistor-free boost LED driver with fast PWM dimming

A boost LED driver features high PWM dimming ratio and optimized efficiency is presented. This LED driver, which having low dropout voltage and is able to drive 3~7 LEDs in series with constant output current and fast PWM dimming, is alternative for brightness adjustment. A dual-path control scheme...

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Bibliographic Details
Published in2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC) pp. 848 - 853
Main Authors Minchao Zhou, Lin Cheng, Danzhu Lv, Zhiliang Hong, Liu, Bill Yang
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.03.2013
Subjects
Current measurement
Light emitting diodes
Mirrors
Pulse width modulation
Switches
Voltage control
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Summary:A boost LED driver features high PWM dimming ratio and optimized efficiency is presented. This LED driver, which having low dropout voltage and is able to drive 3~7 LEDs in series with constant output current and fast PWM dimming, is alternative for brightness adjustment. A dual-path control scheme with automatically state switching and maintenance is proposed. Meanwhile, a cascode current mirror structure is adopted with the output transistor multiplexed as LED PWM dimming transistor. Implemented in 0.5um 25V BCD process, the measurement results show that a voltage conversion range of 5V input to 6~21V output with constant output current is achieved. With automatically switching dual-path control and optimized current mirror, the response time during PWM dimming is reduced to as less as 240ns and the efficiency is kept above 89% over wide PWM dimming ratio @250mA output current.
ISBN:1467343544
9781467343541
ISSN:1048-2334
2470-6647
DOI:10.1109/APEC.2013.6520310