本論文提出具加速機制轉導放大器，操作於電流模式的降壓型直流直流轉換器。為了改善降壓型轉換器在負載巨幅變動下，所造成輸出電壓暫態變化過大與暫態回復時間過長的問題。因此本論文提出具加速機制轉導放大器，其主要利用兩組差動放大器，以感測負載變化載時，輸出電壓下降(或上升)幅度。當輸出電壓(VOUT)變化超過參考電壓(VREF)一參考差值時，加速機制立即啟動，直到輸出電壓回穩，加速電路才會關閉。其中，參考差值可透過調整差動放大器的輸入電晶體之長寬比。根據量測結果，當負載從輕載變重載時(50-500 mA)，輸出電壓變異最大幅度為25 mV，暫態回覆時間為16 μs;當負載從重載變輕載時(500-50 mA)，輸出電壓變異最大幅度為40 mV，暫態回覆時間為16 μs。因此具加速機制轉導放放大器有效改善暫態響應。本晶片採用TSMC 0.35 μm 2P4M CMOS製程實現，晶片面積為1.439×1.430 mm2 (含PADs)。

The proposed area-efficient high-speed operational transconductance amplifier (OTA) is designed for current mode buck converters to alleviate the output voltage variation and to shorten the transient recovery time for load current changes. Two differential pairs in the proposed OTA are used to detect the output voltage variation when the load current changes. If the output voltage variation is across an offset voltage, the high speed circuit will be reacted until the output voltage is back to the regulated value. The offset voltage can be adjusted by designing the size of the input transistors of the two differential pairs. According to measurement results, the maximum output voltage variation and transient recovery time are 25 mV and 16 μs, respectively, for a step-up load from 50 mA to 500 mA. Similarly, the maximum output voltage variation and transient recovery time are 40 mV and 16 μs, respectively, for a step-down load from 500 mA to 50 mA. Hence, the proposed area-efficient high-speed OTA applied in current mode buck converter can improve transient response. The chip is implemented by TSMC 0.35 μm 2P4M COMS Technology, and the size including pads is 1.439×1.430 mm2.

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