本論文實現一類比式可變頻率控制器並整合進電流型降壓轉換器中；隨著可
攜式產品市場之高度成長，對小體積、具快速暫態響應、低成本且高效率之降壓
轉換器的需求逐漸提高；在小電感值條件下設計一穩壓器可有效降低應用電路之
體積及成本，且相較於大電感之應用，先天上即具有較快之暫態響應；但隨著電
感值降低，輸出電壓之漣波將隨之增加，必需以較快之切換頻率減少漣波值，而
此條件將限制切換頻率之選擇條件；較快的切換頻率雖可有效減少輸出電壓之漣
波值，使穩壓器不需增加外部濾波電容值，但將使得與頻率相關成份之功率損耗
隨之而增加。可變頻率控制器可隨負載條件不同變動轉換器之切換頻率，在滿足
額定漣波值之條件下對轉換器之操作效率進行最佳化；可變頻率控制器在此設計
中以類比方式實現並整合於晶片中，不需複雜之控制電路即可完成實現。本論文
除了實現可變頻率控制器之外，亦藉由改善電感電流偵測器之方式，降低控制電
路之功率損耗並提高了中載部份之效率；而此設計亦提供降低偵測時之切換雜訊
之機制，提高偵測信號之品質，完成電流型降壓轉換器之設計。
本論文將此技術應用到電流型切換式直流-直流轉換器是使用TSMC 0.35um
2P4M 3.3V 混合訊號互補式金氧半製程來製作。晶片的全部面積為1.06 x
0.995mm2，此轉換器電路輸入電壓為2.4~3.6V，輸出電壓範圍為0.7~3.3V，最
大電感電流為1A，操作頻率為200kHz 至2MHz，輕載對效率之改善可達5mW，
重載對效率之改善可達20mW。

A current-mode buck converter with integrated analog variable-frequency controller (VFC) is implemented in this thesis. With the highly growing market of the portable devices, a compact, fast, low cost and high efficiency regulator is needed in power management solutions. Design of the regulator with small inductor can significantly reduce the PCB size and cost; and it is inherently faster than general solutions due to higher filtering bandwidth. But small inductor makes higher output voltage ripple, thus the design of switching frequency is limited by the rated output
voltage ripple; faster switching frequency though effectively reduces the output voltage ripple without increasing the output capacitance, but introduces more
frequency-dependent power loss such as switching loss and dead-time loss into regulator. By adapting VFC, which can be easily integrated in a chip without complex control circuts, the efficiency can be optimized under rated output voltage ripple with small inductor value. Furthermore, the proposed current-mode regulator provides an improvement of the current sensor, reducing the controller power loss while
maintaining sensing accuracy, and eliminating the sensed noise, providing better sensed signal quality to the feedback loop, significantly promoting the performance of
current-mode switching regulator.
This current-mode buck regulator is fabricated with TSMC 0.35um 3.3/5V Mixed-Signal CMOS process. The total chip area is about 1.06 x 0.995 mm2. Verification results show that power saving at least 5mW and 20mW during light load
and heavy load individually.

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