| Summary: | 碩士 === 國立臺灣海洋大學 === 電機工程學系 === 99 === In recent years, the smart touch mobile phones, Global Positioning System（GPS）satellite navigation unit, driving recorder, high definition（HD）digital camera, Light-Emitting Diode（LED）lighting, and related electronic products have emerged. It makes the system end of product development companies extensively use microprocessors, digital signal processing（DSP）, and multi-module systems to increase product functionality and meet product demand. Hence, it increases demand for the power of their respective function module. The control of system and system design also increase the difficulty.
In this thesis, we use the mechanism of pulse width modulation （PWM）and pulse frequency modulation（PFM）to control and manage our power regulator which can effectively control the current flow to the output at the right time. When working in heavy load periods, it can sense the temperature of the regulator. When the regulator is operating at temperature T1 to temperature T2, heat is the result of power lost. At this point, the system will reduce the switching frequency of power transistors to reduce switching power consumption and remain at a reasonable frequency to control the problem that low frequency causes higher ripple voltage on the output. In the mean time, the regulator also shuts down the idle circuits to ensure the unnecessary power loss. In addition, to protect the chip at boot time from too large current and being burnt down, the soft start circuit is designed to limit start up current. When the temperature is higher than T1, the soft start circuit is turn off to prevent the output voltage from disturbances. When the temperature is greater than T2, send a signal to start the cooling fan system.
In this thesis, the operation voltage of regulator is from 3V to 5V and the output voltage is 1.8V, and the maximum efficiency is 97.3%. The chip is designed with TSMC 0.35um 2P4M polycide CMOS process.
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