Dual 방식을 이용한 모바일용 DC-DC Converter

In this paper, we design a dual mode DC-DC converter for mobile applications to keep high power efficiency in the all loads range. According to load current, an SFM (switcing frequency modulation) mode is adopted for light load, and a PWM (pulse width modulation) mode is used for middle or heavy loads. The circuits has been designed with Dong-Bu 0.35um BCD process and simulated using HSIM and Hspice. Simulation results show that the range of input voltage is 2.9V∼4.2V, and output voltage is -4.06V. Also power conversion efficiency has 85% for all load current of 10 to 150mA.