A Fast-Transient Current-Mode Buck Converter with Linear Regulation Mode

• Main Authors: Wei-Yi Cheng, 鄭韋億
• Other Authors: Jing-Yuan Lin
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/987sa9

碩士 === 國立臺灣科技大學 === 電子工程系 === 105 === Portable electronic products have become an indispensable part of daily life, and portable electronic products widely use battery as a power source. In order to make electronic devices have long operation time and extend their life span, it is crucial for a power management system. In this paper, a fast-transient current-mode buck converter with linear regulation mode is proposed. The proposed buck converter has a set of auxiliary power transistors at the output stage and a set of auxiliary transistors at the output of the error amplifier. When the acceleration mechanism detects the variation of output voltage due to the change of load current, these two sets of auxiliary transistors will be enabled instantly to improve transient response. In addition, the switching converter at light load switches to linear regulated mode to improve efficiency. The proposed buck converter is implemented in TSMC 0.35μm 2P4M CMOS process. The chip area including I/O PADs is 1.556 x 1.840 mm2. The specifications of the buck converter are input range of 2.5-3.5 V, output voltage of 1.8 V, switching frequency of 1 MHz, and maximum load current of 500 mA. The simulated results show that the transient recovery time is 15 μs and the transient ripple of output voltage is 70 mV when a load current swing is 450 mA. Compared without the proposed accelerated schemes, the transient recovery time is reduced by 40% and the transient ripple of output voltage is reduced by 54.7%.