| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 100 === 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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