| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === A dc-dc voltage-mode boost converter operated in low voltage applications is introduced in this thesis. The boost converter is used to convert Li-ion battery voltage (2.7 V ~ 4.2 V) to 5 V. The synchronous rectification architecture is used to reduce conduction loss and the high efficiency is obtained. At initial operation of the system, sudden current may be generated and soft start circuit is used to avoid this situation and to protect the converter system. When the converter system is operated in discontinuous conduction mode (DCM), higher reversed current will be occurred because of the bi-directional switching of the synchronous rectifier. In order to solve this problem, a zero current detector circuit is designed and power consumption is reduced. Finally, the feedback model is presented and simulated to select suitable compensation networks.
Simulation results show that the efficiency of the boost converter is 94 % with 3.6 V input voltage and 5 V / 250 mA conduction. This circuit is implemented with TSMC 0.35μm 3.3/5 V CMOS technology.
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