一种用于UHF RFID标签的高稳定度时钟电路

Clock generator with high stability for the UHF RFID chip

设计了一种用于无源超高频射频识别标签芯片的时钟生成电路.在传统弛豫振荡器的基础上设置相位控制电容和相关校准电路,使输出时钟频率与工作电压和偏置电流不相关,抑制了电源的波动和偏差所引起的时钟抖动,保证了时钟频率的稳定性.同时,利用正负两种温度系数的电阻的温度补偿作用及相应的校准控制,实现了当温度在较大范围变化时时钟的周期稳定性.该电路在TSMC 0.18μm工艺下流片.测试结果显示,该方法可以获得更大的时钟校准范围和更高的输出时钟精度,电路功耗0.86μW,适合无源芯片的使用.

An improved design of the clock circuit is proposed for passive UHF radio frequency identification tag chips.Through the dynamic adjustment of the control circuits by setting capacitances and relevant calibration circuits in the traditional relaxation oscillator circuits,irrelevance is realized between the clock frequency and the working-voltage and bias current,so that the clock jitter caused by power fluctuations and deviation is suppressed so as to guarantee the stability of the clock frequency.At the same time,two kinds of resistance with positive or negative temperature coefficient and calibrating circuits are adopted to keep the clock cycle stability within a large scope of temperature variation.This circuit has been taped out with TSMC 0.18μm process.Test results show that the proposed circuits can get a more calibration scope and clock precision with power consumption of 0.86μW,which is very suitable for passive chips.