A White LED Driver Using a Buck–Boost Converter

Abstract

For mobile backlighting applications, a white LED (WLED) driver using a buck-boost converter is proposed in this letter. Unlike conventional converters using boost converters, 2×/1.5× charge pumps, and so on, the proposed converter offers the negative stepped-down voltage to drive the LED's cathode only when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike the LED backlight using charge pumps, the proposed converter can adjust the output voltage by controlling the duty factor of the clock pulse. Thus, the proposed converter can realize high power efficiency. The validity of the proposed converter is confirmed by simulations and experiments. 

A Negative Single-Input/Multi-Output LED Driver and Its Analysis Method

“…Therefore, the inductor-based LED driver achieves higher efficiency than capacitor-based LED drivers. Following this study, the LED drivers using an SISO buck-boost converter have been proposed [6]- [9] to regulate the LED currents supplied with a wide-range input voltage source. As in the case of the negative charge-pump, the LED driver using a buck-boost converter drives the LED's cathodes.…”