与工艺、电源电压和温度无关的低功耗振荡环设计

Low Power Ring Oscillator Insensitive to Process,Voltage and Temperature

分析了传统片外时钟和片内时钟各自的特点和应用背景,在Chartered 0.35μm CMOS工艺下实现了一个低功耗PVT（工艺、电源电压、温度无关）振荡环,对片内时钟的稳定性和功耗进行改进。该振荡环无需精准的电压源,采用了误差补偿技术,通过偏置电压和延时单元的相互补偿,使得振荡频率对于工艺、温度和电源电压均有较大的容差能力。并且由于针对延时单元补偿的方式,令周期大小易于调整。蒙特卡罗仿真显示,工艺误差引起的偏差要比补偿前的偏差减小了60%。流片测试结果表明,在工作温度变化范围0~100°C时,振荡环输出的频率偏差为±3.22%;在电源电压变化范围为2.8~3.8 V时,振荡环输出的频率偏差为±3.36%;在电源电压3.3 V的情况下,整个芯片消耗的电流为950μA。

This paper analyzes the characteristics of a novel external clock and on-chip clock.The low power PVT（process、supply voltage and temperature insensitive） ring oscillator is designed and fabricated on Chartered 0.35 μm CMOS process. The deviation compensation technology is used to achieve high performance of stability and power consumption.The tolerance of frequency to variation in process、supply voltage and temperature is significant improved by the compensation technology without a voltage reference.The cycle value is easy adjustable for the compensation method to delay cell.The simulation of Monte Carlo prove that the variation of frequency caused by process variation is decreased to 40% compared with uncompensated value.And the experiment results show that the frequency of ring oscillator achieves within ±3.22% variation at temperature range from 0 °C to 100 °C and within ±3.36% variation at the power voltage range from 2.8 V to 3.8 V.And the supply current of whole chip at 3.3 V supply voltage is 950 μA.