一种低成本高精度环形振荡器的设计

Design of a low cost and high accuracy ring oscillator

本文设计了一款输出频率为20MHz的环形振荡器,此振荡器基于一种锁频环技术,不需要使用LC谐振电路,晶振,和MEMS振荡器即可实现。同时详细分析了环形振荡器中使用的补偿技术,包括温度补偿和电压补偿。运用低压差稳压器、数字修调、电流基准电路,使得输出频率精度受工艺漂移、温度波动、电源电压变化影响较小。电路设计工艺为东部的0.18μm BCD。仿真工作条件为:温度范围-50~150摄氏度,电压范围3~5.5V,在5个工艺角下仿真,仿真结果表明,在相同的工作条件下,经过补偿技术的电路频率稳定性得到了显著的提高,电源电压的工作范围得到了提升。

This paper design a high accuracy ring oscillator with an output frequency of 20MHz.This generator is based on a simple frequency-locked-loop technique and can be implemented monolithically without using LC resonant circuits,quartz resonators,and MEMS oscillators.And analyzes the temperature and supply voltage compensate principle.Use low dropout voltage regulator,digital trimming and current reference circuit,the accuracy of the output frequency has a little influence on process drift,temperature fluctuations or the supply voltage change.The circuit design process is DB 0.18 μm CMOS.The condition of simulation is: temperature range from -50 to 150 degrees Celsius, supply voltage from 3 to 5.5V,simulation in the five process angle. The simulation results shows that after temperature and supply voltage compensate the frequency stability is improved significantly and the operating range of the power supply voltage is improved under the same operating condition.