Design of a High Efficiency Dual-Mode DC-DC Boost Converter with Smart Switch Control

• Main Authors: Wang, Kun-Tang, 王琨堂
• Other Authors: Yeh, Mei-Ling
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/06704360443181685187

碩士 === 國立臺灣海洋大學 === 電機工程學系 === 105 === In recent year, the technology industry has developed rapidly, smart phones have become an indispensable part of our lives. The mobile phone functions are not limited to call, but also include the camera, play games, internet, etc., the functions are more and more diversity. A battery needs to supply power to many different modules in the smart phone, so we need strong and stable power management systems to maximize the performance of the battery. In this thesis, a dual-mode boost converter is designed with voltage mode, pulse width modulation, and pulse frequency modulation. When the current is at heavy loads, the converter operates in pulse width modulation which has high conversion efficiency. However, the switching loss of the pulse width modulation mode is a fixed value, and the conversion efficiency at light loads is not well. So when the current is at light loads, the converter operates in pulse frequency modulation, reducing the switching losses to improve efficiency at light loads. Because different sizes of power transistors work in each load have different conversion efficiency, in order to achieve the highest efficiency, we divide the power MOSFET into A, B, and C three parts and by sensing the load current to open the corresponding parts and maintain the conversion efficiency of the whole circuit. This thesis is implemented with TSMC 0.35um Mixed-Signal 2P4M Polycide process provided by National Chip Implementation Center. The range of the input voltage is from 3 V to 3.9 V and the output voltage of the converter is steady in 5 V. The converter operates at switching frequency 1.1 MHz, the inductor is 10 uH, and the capacitor is 10 uF. The output ripple voltage of the system operating in the pulse width modulation mode is 20 mV. While operating in the pulse frequency modulation mode, the output ripple voltage is 30 mV. The load current range is 25 mA to 400 mA. When the load current is 50 mA, the conversion efficiency is 88.3% at pulse frequency modulation mode. The maximum conversion efficiency is 93.5%, and the area of the chip is 2.149×1.978 mm2.