提出一种适用于无源超高频射频识别 (UHF RFID)标签芯片的时钟产生电路。电路使用 N型金属-氧化物-半导体 (NMOS)栅极电压取代了复杂的比较器电路作为比较电平, 精简了电路结构, 降低了电路功耗, 减小了版图面积; 使用二极管方式连接的 NMOS管作温度及工艺补偿感应管, 利用其栅压变化控制充放电电流, 使其在不同工艺角下, 当温度在较大范围内变化时, 均能实现输出频率稳定。采用中芯国际 0.18 μm工艺进行仿真验证, 结果表明：当电源电压为 1V, 基准电流为 130 nA时, 电路功耗仅为 447 nW; 在工艺角由 ss变化到 ff的过程中, 输出频率偏差不超过 2.43%,; 温度在-40~90 ℃范围变化时, 输出频率偏差小于 0.99%, 适合无源射频识别标签芯片使用。

A clock generation circuit that is suitable for passive Ultra High Frequency Radio Frequency Identification(UHF RFID) tag chips is proposed. Different from the traditional relaxation oscillator structure, the N-Metal Oxide Semiconductor(NMOS) gate voltage is utilized as a comparisonreference level, without the need of complex comparator circuit. The circuit structure is simplified, whichgreatly reduces the power consumption and reduces the layout area. At the same time, the NMOS transistoris adopted for temperature and process compensation, the gate voltage of which is utilized to control the charge and discharge current. The output frequency is stable without traditional clock calibration. The circuit is designed in a standard Semiconductor Manufacturing International Corporation(SMIC) 0.18 μmComplementary Metal Oxide Semiconductor(CMOS) technology, with the condition of 1 V power supply voltage and 130 nA reference current, and the power consumption of this circuit is only 447 nW. When theprocess corners are changed from ss to ff, the output frequency deviation is no more than 2.43 %, and the temperature changed from-40 ℃to 90 ℃, the output frequency deviation is less than 2.62%, so the circuit is suitable for passive RFID tag chips usage.