整合紅外線溫度感測器操作於1V之被動式2.45GHz RFID詢答器設計

本論文設計並實現一整合紅外線溫度感測器操作於1V之被動式2.45GHz RFID詢答器晶片，此晶片包含了溫度感測器、讀取電路、逐漸趨近式類比至數位轉換器(SAR ADC)與被動式無線射頻辨識詢答器(RFID)。溫度感測器是採用微機電(MEMS)製程，設計一甕形結構體(Urn-Shaped Structure)，以蝕刻的方式將金屬層刻出孔洞，使紅外線在此結構體中產生繞射與多重反射現象，以利提升能量的吸收率。SAR ADC採用雙頻(Dual-Frequency)的工作模式，使取樣時間得以配合低反應速率的熱感測器與讀取電路，並維持SAR ADC本身的高轉換速率。RFID詢答器以接收距離一公尺的0.5W EIRP 2.45GHz 250mVpp的射頻訊號來驅動與供應能量。本論文採用國家晶片系統設計中心所提供的TSMC 0.18μm 1P6M CMOS-MEMS製程來設計與實現此晶片。熱感測器與讀取電路的操作電壓在1V時，溫度感測範圍與輸出電壓分別為：-25℃ ~ 95℃與236mV ~ 901mV，靈敏度約為5.54mV/℃，功率消耗約為70μW；相對於ADC的數位輸出為00111010(58)~11101000(232)。SAR ADC操作電壓於1V，工作頻率為2.4MHz，輸入弦波頻率為40.3125KHz時，SNDR為49.467 dB，ENOB為7.925-bit，功率消耗為2.8043μW，FOM為48.08 fJ/conversion。整體晶片面積(含PAD)為950.545×965.04μm2，功率消耗約為85μW。

關鍵字

低功率；熱感測器；讀取電路；逐漸趨近式類比至數位轉換器；雙頻時脈； 2.45GHz被動式詢答器

並列摘要

In this thesis, a 1-V 2.45GHz passive RFID transponder with integrated infrared sensor is presented.The chip contains temperature sensor, readout circuit, SAR ADC and passive RFID.The temperature sensor of the urn-shaped structure uses MEMS process to etch a cavity in the metal later for resulting diffraction and multiple-reflection in the etched cavity to increase the absorbed infrared energy.The SAR ADC adopts the dual-frequency method to generate a 2.4KHz clock for sample and hold, and a 2.4MHz for digital code conversion. The RFID transponder chip can receive 0.5W EIRP 2.45GHzincident RF signal from 1-meter to drive circuit and supply the energy. The chip is implemented using TSMC 0.18μm 1P6M CMOS-MEMS process provided by CIC.The thermal sensor and readout circuit work at 1V power supply, and the power consumption is less than 70μW. When tempeteature changes from -25℃ ~ 95℃, the voltage output is 236mV ~ 901mV and the digital output is 00111010 ~ 11101000.The simulation results of the ADC show that the SNDR and ENOB are 49.467 dB and 7.925-bit at 240KS/s sampling rate, respectively and 2.8125KHz input frequency with power consumption of 2.8043μW from a 1V supply voltage.The FOM is 48.08 fJ/conversion.The whole chip area is 950.545×965.04μm2, and power consumption less than 85μW.