| Summary: | 碩士 === 國立中興大學 === 電機工程學系所 === 94 === The content of this thesis is to design and realize a DC to DC buck converter. The control methods of the converter are analyzed and designed including current mode pulse width modulation, voltage mode pulse width modulation, and pulse frequency modulation. It is suitable for electronic system applications and to prolong the usage time of batteries such as digital camera, PDA, mobile phone, etc. Wide range, high conversion efficiency, fast transient response, and automatically switching of the control method are the research topics of this thesis.
For switching buck converter, in order to enhance the efficiency range of the whole system, two control methods including pulse width modulation and pulse frequency modulation are adopted for heavy load and light load condition, respectively. This thesis proposed a novel control method selector, which can effectively and accurately switch over the suitable method of the situation at that time. In light load condition, needs the technique for reducing the unnecessary power consumption to improve the conversion efficiency. Moreover, the soft start circuit is designed to eliminate the excess large current at the start up of the converter that may damage the internal devices. When the two modes are switched appropriately, the conversion efficiency could be up to 90.5%.
The DC-DC voltage converter is designed and fabricated with TSMC CMOS 0.35μm 2P4M 3.3V/5V Mixed Signal technology. The chip size is about 1.46 1.46 mm². The range of the operation voltage is form 2.4V to 3.6V.In the best case, the load regulation and line regulation are 0.034 %/A and 0.032%/V separately. The others important characteristic and performance will be described in the following chapters of thesis.
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