Abstract—This paper presented a white light emitting diode (LED) driver that utilized charge pump in boosting the input voltage. The output voltage had been made sure that it was sufficient enough to overcome the forward voltage of the LED as well as provide voltage headroom for the transistors in every LED channel branch. The charge pump and its peripheral circuit, the clock booster circuit, do not suffer from gate-oxide overstress. Gate oxide overstress arose when the potential difference of a certain junction of a transistor exceeded the supply voltage. Moreover, this design can accommodate four (4) LEDs arranged in parallel. In comparison with the other DC-DC converters such as buck and/or boost, this work does not utilize an inductor. The non-utilization of inductor has offered an advantage in terms of lesser board area consumption and minimal height. The test chip was implemented using 0.35μm 5V 2P4M CMOS process. The chip area was measured to be 2350.05μm x 2496.70μm with an efficiency of 51%.

Index Terms—overstress, non-overstress, charge pump, white LED driver

Cite: Allenn dela Cerna Lowaton and Hong-Yi Huang, "Overstress-Free Charge Pump White LED Driver," International Journal of Electronics and Electrical Engineering, Vol. 2, No. 4, pp. 270-275, December 2014. doi: 10.12720/ijeee.2.4.270-275