Fig. 1.
Simplified system architecture of the proposed boost LED driver.
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| Citation: |
Minchao Zhou, Danzhu Lü, Lin Cheng, BillYang Liu, Zhiliang Hong. A dual-path, current-sensing resistor-free boost LED driver with fast PWM dimming[J]. Journal of Semiconductors, 2013, 34(4): 045005. doi: 10.1088/1674-4926/34/4/045005
M C Zhou, D Lü, L Cheng, B Liu, Z L Hong. A dual-path, current-sensing resistor-free boost LED driver with fast PWM dimming[J]. J. Semicond., 2013, 34(4): 045005. doi: 10.1088/1674-4926/34/4/045005.
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A dual-path, current-sensing resistor-free boost LED driver with fast PWM dimming
doi: 10.1088/1674-4926/34/4/045005
More Information-
Abstract
A boost LED driver featuring a high PWM dimming ratio and optimized efficiency is presented. This LED driver, which has a low dropout voltage and is able to drive 3-7 LEDs in series with constant output current and fast PWM dimming, provides an alternative technique for brightness adjustment. A dual-path control scheme with automatic switching and state maintenance is proposed. Meanwhile, a cascode current mirror structure is applied with the output transistor multiplexed as an LED PWM dimming transistor. Implemented in 0.5 μm 25 V BCD process, the measurement results show that a voltage conversion range of 5 V input to 6-24 V output with constant output current is obtained. With automatically switching dual-path control and an optimized current mirror, the response time during PWM dimming is reduced to as low as 240 ns and the efficiency keeps above 89% over a wide PWM dimming ratio@250 mA output current.-
Keywords:
- boost LED driver,
- constant current,
- fast PWM dimming,
- dual-path,
- multiplex,
- efficiency
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References
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