A Dual Path Hybrid Step-Up Converter with Enhanced Drive Voltage for Low Voltage Applications

A novel dual path hybrid step-up (DPSU) converter is proposed in this paper. An inductor and a flying capacitor are adopted as power conversion elements. The proposed converter can produce a higher conversion ratio (CR) with the same duty cycle compared to conventional boost (CB) converter. The voltage stress of power devices is relieved in the DPSU converter and the average inductor current is also reduced leading to lower power loss caused by dc resistance (DCR) of inductor. Furthermore, a negative-voltage switching node is obtained by DPSU converter and a charge-sharing based bootstrap gate driver is designed. The bootstrap gate driver takes use of the negative-voltage switching node, which can enhance driving voltage even at low input voltage. Circuit design is therefore simplified and efficiency is further improved. Simulation results show when input voltage and load current is 2.7V and 1A respectively, the conversion efficiency of DPSU converter is 11.34% higher than that of CB converter.