目前常見的降壓型控制器，為了能夠得到較高的效率，通常會在重載時採用脈波寬度調變模式，輕載時採用脈波頻率調變模式，而此方法需要使用電流感測器判斷電感電流是否為零，才能使轉換器的控制方式根據負載的不同，自動轉換脈波寬度調變模式和脈波頻率調變模式。
本篇論文採用無電流感測之技術，不需要電流感測器偵測電感電流，即可達到自動轉換模式之功能。優化此判斷兩種模式轉換的演算法，使電路面積與功耗減少，本文之控制器將切換頻率提高，以降低穩態下之輸出電壓漣波，並加入短路保護機制，當短路故障發生時會自動將開關關閉，避免短路故障而使元件損壞。
使用FPGA(DE2-70)驗證功能且實作降壓型轉換器，輸入電壓為 3~4.2 V，輸出電壓為1.2 V，最高效率為86 % @Io=0.5 A，並且使用TSMC 1P6M 0.18 μm Cell-Based 製程下線。

The common buck converter is used the pulse width modulation (PWM) mode under the heavy load and the pulse frequency modulation (PFM) mode under the light load to obtain the high efficiency. The control method, switching the PWM mode and the PFM mode automatically depend on the different loads, needs the current sensor to judge whether the inductor current is zero or not.
The thesis uses the no current sensing technology which switches the two modes automatically without the current sensor. In addition, optimize the algorithm to make the area and cost of the control circuit less than before and increase the switching frequency of the converter to obtain the less output voltage ripple. Further, add the short circuit protection function which turns off the switches when the short circuit fault occurs to prevent damaging the components.
Use the field programmable gate array (FPGA) to verify the functions and implement a buck converter which has 3~4.2 V input voltage, 1.2 V output voltage and 86% highest efficiency under 0.5 A output current. After the FPGA verification, the control circuit has been implemented in TSMC 1P6M 0.18 μm CMOS technology.

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