A 91.15% Efficient 2.3-5-V Input 10-35-V Output Hybrid Boost Converter for LED-Driver Applications

This article presents a hybrid boost converter architecture for improving the efficiency of light-emitting diode (LED) drivers used in mobile applications. By cascading a low-switching frequency time-interleaved series-parallel switched-capacitor (SC)-stage with an inductive-boost converter, we facilitate lower voltage-rated switches, thus significantly reducing the switching losses. Charge-sharing losses of the SC stage are minimized by soft-charging flying capacitors with the inductor of the boost (BST) stage. Fabricated in 180-nm bipolar CMOS DMOS (BCD) process, the prototype converter generates 30-V output voltage from a Li-ion battery source. It can provide a load current in the range of 0-100 mA with an excellent peak power efficiency of 91.15% at 30 mA, which represents a 3% improvement over the state of the art.