使用開關調變與頻率縮放技術 的可重組式切換式電容直流電源轉換器

Reconfigurable Switched Capacitor DC-DC Converter With Adaptive Switch modulation and Frequency scaling technique

廖敦彥(Tun-Yen Liao)

指導教授 ： 陳信樹

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201904318

摘要

近年來，低功率消耗的穿戴式裝置晶片以及生醫上的晶片應用蓬勃發展，人們需要低成本小體積的直流電壓轉換器的解決方案。全電容式的直流電壓轉換器因為其體積與功率密度比起電感式的直流電壓轉換器更具有優勢而再度受到重視。在物聯網的應用上，大部分的裝置長時間都處於待機模式(Standy mode)，直流電壓轉換器無載時的靜態電流消耗也影響了產品的使用時間，低靜態電流的設計也成為全電容式電壓轉換器設計的難題。
本論文會講解不同的電容式轉換器的操作原理，並且分析電路設計與效率的關係進而去設計出效率最佳的直流電壓轉換器。並且探討不同控制方法，並結合其優點符合物聯網應用的需求。
受限於輸入端的儲能裝置如電容或者電池，輸入電壓會隨著使用時間降低成為全電容式直流電壓轉換器的瓶頸。本作品提出的全電容式直流電壓轉換器，可根據輸入電壓的不同改變其除數(1/2,2/3)達成一個可重組的架構改善全電容式直流電壓轉換器的效率受限於單一架構的問題。在回授的控制上融合了開關調變的機制與降低動態比較器頻率的機制，當負載改變時電路會自動調節開關的大小以達到最大的效率值。透過台積電0.25μm 1P3M High Voltage Mixed Signal CMOS製程實現，依據實驗結果，本晶片在瞬間抽載時，暫態反應時間約為0.6μs，負載電流範圍從50微安培(μA)到12豪安培(mA)，最高效率為83%。

關鍵字

全電容式直流電壓轉換器 ； 開關調變機制 ； 頻率縮放 ； 動態基底偏壓 ； 低靜態電流

並列摘要

Recently, people need the solution of DC-DC converter that can save a lot of cost and size because the application of low power wearable devices and biomedical devices flourish. People pay attention to Switched Capacitor (SC) DC-DC converters because it is more competitive on size and power density than inductive power converter. In the IoT (Internet of Things) application, most of the time most devices are on the standby mode so that they only need very small current. In this mode, the quiescent current of the power converter will affect the lifetime of the device. Therefore, how to design a low quiescent SC DC-DC converter is a big challenge.
This thesis explains the operation theory of different SC DC-DC converter and analyzes the correlation circuit design between efficiency so that it can help us to design maximum efficiency switched capacitor. This thesis combines different control technique’s advantages to meet the application needs of the IoT.
The SC DC-DC converter present by this thesis can change open-loop topology (1/2, 2/3) according to different input voltage so that it can overcome the efficiency problem of one topology SC DC-DC converter. Also, this work combines the mechanism of adaptive switch modulation and changing the sampling rate of the dynamic comparator for maximum efficiency tracking when load condition changes. This chip implement in the TSMC 0.25μm 1P3M High Voltage Mixed-Signal CMOS process. This converter provides a fixed output voltage of 1.8V at 50μA ~ 12mA from 3V to 5.4V. The peak efficiency is 83%.

並列關鍵字

Reconfigurable Switched-Capacitor DC-DC converter ； Adaptive Switch modulation ； Frequency Scaling ； Dynamic body bias ； Low quiescent current

參考文獻

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