一种新型高精度的R C振荡器设计

A New High Precision RC Oscillator Design

提出一种改进型的基于0.18μm CMOS工艺的新型高精度RC振荡器电路,其整体结构中只使用一个比较器,利用参考电压和反馈电压比较来产生时钟脉冲。采用开关电容模块来产生与时钟频率和电源电压成比例同时受温度影响较小的参考电压,利用周期控制结构来产生反馈电压。由于在参考电压生成中引入了时钟脉冲,消除了比较器失调和延时的影响,提高了精度,整体结构简单,振荡频率较高,功耗较小,振荡中心频率为20 MHz,功耗18μW,在-40℃-125℃温度范围内,可实现±0.5%的精度。

This paper presents a new type of high precision RC oscillator circuit based on 0.18 μm CMOS technology,in which only one comparator is used to generate clock pulses by comparing the reference voltage with the feedback voltage. Switched capacitor module is used to generate reference voltage which is proportional to clock frequency and power supply voltage meanwhile is less affected by temperature. Periodic control structure is used to generate feedback voltage. Due to the introduction of clock pulse into the reference voltage generation,the influence of the comparator offset and delay is eliminated,and the accuracy is improved. The overall structure is simple,the oscillation frequency is high,and the power consumption is small. The oscillation center frequency is 20 MHz,and the power consumption is 18 μW. In the temperature range of - 40 to 125 ℃,the accuracy of ±0.5% can be achieved.