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# International Conference on Instrumentation, Measurement, Circuits and Systems (ICIMCS 2011)

By
Chen Ming
Chen Ming
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ISBN:
9780791859902
No. of Pages:
1400
Publisher:
ASME Press
Publication date:
2011

A high efficient inverting-charge-pump White LED(WLED) driver is presented. The driver employs a 1x/−0.5x inverting charge pump, five Low-Dropout current regulators and self-adjusting mode control for each WLED. Due to employing inverting charge pump, the driver does not require bypassing the output of inverting charge pump to ground in 1x mode, which eliminates the effect of bypass switch's dropout voltage. The mode control circuit provides individual self-adjusting mode switch for each WLED, which avoids the effect of WLEDs' forward voltage($VF$)'s mismatch. The two points above inceases the efficiency of the driver. The proposed driver is designed by 0.5um BiCMOS process. Simulation and experimental results show that the driver is able to achieve high efficiency (averaging 84%) which is comparable with inductor-based driver while benefiting from the simplicity and cost savings offered by charge-pump solutions. The driver is able to drive 5 parallel WLEDs and each WLED channel allows 20mA output current.

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