低功率電流模式雙斜率式互補金氧半溫度感測器

Abstract

本論文貢獻了一種溫度感測的新可能，並且呈現一個可行的原型。本篇論文將介紹一個新穎的低成本低功率雙斜率式溫度感測晶片。本晶片使用了一個正比於絕對溫度(PTAT)的電流產生器，其運作在電晶體的次臨界區。另外還用了一個對溫度不敏感的互補式金氧半電晶體反向器，此反相器用以產生一個PTAT脈寬之脈波，並可以取代傳統式的電壓比較器，節省了更多功耗與面積。輸出之PTAT脈波接著以一個二進位計數器來做數位量化。本溫度感測晶片，在-40°C到85°C的工業溫度範圍內，達到-3.39/+2°C 以內的誤差，而平均溫度解析度可達0.259°C/LSB。感測器的轉換率達到3.5 kSa/s，而且只需2V電壓即可使用，功耗僅14.286 μW，能源效率可達4.082 nJ/Sa，並擁有0.274 nJ°C2 的resolution FoM。本晶片以TSMC 0.35 μm CMOS 製程實現。核心電路所占面積僅0.0345 mm2。

其中晶片採用的雙斜率架構集合結構精巧、省電、高解析度與精確度、高設計彈性、免熱電偶等等的眾多優點，以相當成熟又低成本之製程即可實現，不需價格高昂的製程。它非常適合用於快速溫度監測、電路系統之熱管理，適合整合進任何積體電路及晶片封裝。可以用於任何可攜式裝置、消費性電子、生醫電子、空調與製冷、工業生產、車用電子，亦可輕易用在任何物連網裝置中。

This dissertation contributes a new possibility for temperature sensing and presents a feasible prototype. A novel low-cost low-power dual-slope CMOS temperature sensor is presented in this dissertation. It employs a proportional-to-absolute-temperature (PTAT) current generator, which operates in the sub-threshold region, and a novel temperature-insensitive CMOS inverter, replacing a traditional voltage comparator for power saving and compactness, to create PTAT pulse width. A binary counter is then used to quantize the pulse to a digital output value. It achieves a temperature inaccuracy of -3.39 °C to +2 °C over the common industrial temperature range from -40 °C to 85 °C for five measured chip samples, and an average temperature resolution of 0.259 °C/LSB. The conversion rate of the digital output is 3.5 kSa/s. 2 V supply voltage is used and total power dissipation is 14.286 μW, leading to 4.082 nJ/Sa energy efficiency and 0.274 nJ°C2 resolution FoM. It was fabricated by TSMC 0.35 μm CMOS process and the core area occupies 0.0345 mm2.

The used dual-slope architecture has the advantages of compactness, power-saving, high resolution, good accuracy, high design flexibility, and relieving the use of the extra off-chip thermocouple. It can be implemented by common CMOS process. The sensor is suitable for rapid temperature monitoring, consumer electronics, biomedical electronics, air conditioner or refrigerator, industry, automotive electronics, and any IoT (internet of things) device.