應用於女性排卵監控系統之多軸讀出電路

Abstract

在本篇論文中，我們提出了一個用於幫助女性偵測排卵期的監控平台，包含監控使用者的溫度及行為。根據本篇論文所提出的應用，我們實現了五組的讀出電路，其中三組為電容式，用於偵測加速度計的XYZ三個方向所產生出的電容值變化，以及兩組為電阻式讀出電路，分別用於偵測晶片外部的人體溫度，及偵測晶片自身的溫度，再藉由晶片的溫度去校正讀出電路因溫度變異而造成電路輸出的影響。另外還使用兩種優化電路的架構，其一是為了降低在製程上所帶來電阻及電容的不匹配，對電路輸出造成的偏移，我們使用降低輸出偏移的補償方法，以及為了減少因製程、電壓、溫度所造成變異對結果造成的影響，所以採用對輸出結果取比例的方式去解決。最後我們還實現硬體共用以及事件驅動方法，去降低功耗以增加系統效能。 本論文所提出的多軸讀出電路使用UMC 0.18µm CMOS-MEMS製程實作，模擬結果顯示電容式讀出電路解析度為0.1f；電阻式讀出電路可以達到感測範圍0~100°C與0.05°C之解析度。在這個多軸電路中，當只開啟單軸讀出電路時，運作在轉換時間為0.8ms，供電電壓為1.8V時功率消耗約為30µW。

In this thesis, we proposed a monitoring platform that can help women detecting their ovulation. It includes temperature and motion sensing circuits that can translate differential capacitance and resistance from sensing-ends into digital code. According to the application in this thesis, we implement five sensors in our design. Three of them are capacitance sensing circuits which induced by accelerated motion of triaxial accelerometer. The other two are resistive sensing circuits that are used to detect die-temperature and human body temperature. The die-temperature effects the results of sensor circuits that can be calibrated by sensor fusion. There are some methods for us to optimize the performance of this design. First, it decreases the offset of capacitance and resistance mismatch caused by its process or parasite. Second, it takes proportion in order to reduce effect from P-V-T variations. Finally, the hardware-sharing and event-driven architecture makes this system save more power and area. This thesis proposed a multi-axis readout circuit which is fabricated in the process of UMC 0.18µm CMOS-MEMS technology. The simulation results show that the resolution of capacitive readout circuit is 0.1fF. Resistive readout circuit can achieve sensing range is 0~100°C with 0.05°C resolution. In this multi-axis readout circuit, when only turn on 1-axis readout circuit with 1.8V of supply voltage, it will consume about 30µW in 0.8ms conversion time.