由於切換式降壓型轉換器在輸入側容易會有過大的電磁干擾問題，本論文所提出的具隨機切換頻率之固定導通時間控制降壓型轉換器主要特色為在不增加外部元件的情況下，在控制端使用 展頻機制降低轉換器本身的電磁干擾。同時轉換器的功率級輸出電容可使用積層陶瓷電容，其低串聯等效電阻的特性可以降低輸出電壓漣波的大小且積層陶瓷電容比起電解質電容擁有體積小、良好的高頻響應、較長的使用壽命等等優點。本論文晶片採用TSMC 0.18μm 1P6M CMOS 製程實現包含內部核心電路與PADs之晶片面積為 1.2×1.15 mm2。輸入電壓範圍2.7~3.3 V以及輸出電壓為 1.8 V，負載電流範圍為50~700 mA，外接功率級電感與電容分別為3.3 μH與10 μF。量測結果顯示當負載電流變化為500 mA時，暫態回復時間約為5 μs，轉換器最高效率在200 mA為 94 %，最低效率在50 mA為87 %。

Since the switching buck converter is prone to excessive electromagnetic interference on the input side. The constant on-time controlled buck converter with random switching frequency proposed in this thesis is mainly characterized by not adding external components. In this case, the spread spectrum mechanism is used at the control end to reduce the electromagnetic interference of the converter itself. At the same time, the output capacitor of the converter can use a multilayer ceramic capacitor, and its low series equivalent resistance can reduce the output voltage ripple. Moreover, the multilayer ceramic capacitor has the advantages of small volume, good high frequency response, long service life and the like compared with the electrolytic capacitor. The chip had been implemented with TSMC 0.18-μm 1P6M CMOS technology and its chip size including pads was 1.2×1.15 mm2. The input voltage range is 2.7~3.3 V and the output voltage is 1.8 V. The load current range is 50~700 mA. The external power stage inductance and capacitance are 3.3 μH and 10 μF respectively. The measurement results show that when the load current changes to 500 mA, the transient recovery time is about 5 μs, the maximum efficiency of the converter is 94 % at 200 mA, and the lowest efficiency is 87 % at 50 mA

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