面向RFID标签的COMS低功耗温度传感器设计

Design of COMS Low Power Temperature Sensor for RFID Tag

为了最大限度地提高无线射频识别(RFID)标签的操作距离,提出了一种集成于RFID标签芯片的超低功耗高精度CMOS温度传感器。提出传感器电路由新型数字环形振荡器,分频器,多路复用器和10 bit的数字计数器组成,温度转换成数字输出是在一个采样周期期间通过计数振荡器的时钟边缘数量得以实现。振荡器的频率可以通过电容器组和堆叠晶体管进行数字修正。通过0.18μm CMOS测试芯片获得的测量数据表明,提出的温度传感器分辨率为0.4℃/LSB,10 bit数字输出,校准后的可测量温度范围从-20℃到95℃。采样频率为10 Hz时,提出的传感器的功耗仅为92 n W。

In order to improve the operating distance of wireless radio frequency identification（RFID）tags,an ultra-low power high precision CMOS temperature sensor integrated with RFID tag chip is proposed. The sensor circuit is composed of a new type of digital ring oscillator,a frequency divider,a multiplexer,and a 10 bit digital counter. Temperature is converted into digital output which is achieved during a sampling period by the number of the clock edge of the oscillator is obtained. The frequency of the oscillator can be corrected by means of a capacitor stack and a stack of transistors. Due to the temperature dependence of the threshold voltage and the carrier mobility of MOS transistor,the proposed sensor is simpler than the traditional temperature sensor. The measured data obtained by 0.18μm CMOS test chip show that the proposed temperature sensor resolution is 0.4℃/LSB,the 10 bit digital output,the calibration can be measured in the temperature range from-20℃to 95℃. When the sampling frequency is 10 Hz,the power consumption of the proposed sensor is only 92 nW.