Analysis and Design of a High Efficiency Boost DC-DC Converter Based on Pulse-Frequency Modulation

A high efficiency boost DC-DC converter controlled by current-limited and minimum off-time pulse-frequency modulation (PFM) mode is analyzed in this paper. The boost converter operating in discontinuous conduction mode (DCM) is modeled by the state-space average method, and is simulated by Matlab. The converter controlled by this PFM has lower power consumption, higher efficiency, smaller output ripple, and better regulation. The converter is designed and simulated using the UMC 0.6 mum 30 V BCD process. Hspice simulation results show that, the converter can operate with supply voltage from 2.7 V to 5.5 V, and boost voltage up to the fixed 15 V steadily. The output ripple voltage is about 220 mV with 1 muF capacitor and 22 muH inductor. The power efficiency is nearly above 80% for the full load, maximum to 87%.