基于脉冲调制技术的RFID标签集成温度传感器

摘要

设计了一种集成于无源超高频射频识别（ UHF RFID）标签的温度传感器。针对标签功耗受限、芯片面积小的特点，利用MOS管电子迁移率随温度变化的规律，设计双偏置电流源的温度转换电路，产生宽度受温度调制的脉冲，实现温度的采集，提高传感器精度。并且设计以异步计数器为基础温度转换电路替代模数转换电路（ ADC）实现温度到数字输出之间的转换。采用SMIC 0．18 CMOS工艺对温度传感器电路进行仿真，仿真结果表明，温度传感器感应温度范围为－20～60℃时，分辨率为1℃／LSB，电源电压为1．8 V时，室温下传感器芯片总的工作电流为400 nA。%A kind of passive RFID tag embedded temperature sensor was designed in the paper.Due to the limited power dissi-pation and chip area,a temperature converter with double current biases was proposed,which utilizes MOS electron mobility tem-perature theory to generate temperature modulated pulse,realizing temperature sampling and improving accuracy of the temperature sensor.Simultaneously,an asynchronous counter was designed to realize temperature to digital data conversion instead of ADC.The circuit was ricated by SMIC 0.18 CMOS standard process.The simulation results indicate that the temperature senor achieves a reso-lution of 1℃/LSB from -20℃to 60℃.At 25℃,the working current of sensor draws 400 nA from 1.8 V supply.