一种新型高精度低功耗的张弛振荡器设计

A New Design of High Precision Low Power Relaxation Oscillator

针对传统张弛振荡器精度低的问题,设计了一种低功耗、高稳定度的张弛振荡器。该振荡器由RC充放电模块、有源滤波器模块以及偏置模块组成。采用单比较器实现电位反转,降低整体的功耗,通过使用温度特性相反的电阻混合对温度变化进行补偿,以及有源滤波器产生电压反馈以实现输出时钟信号高精度。采用SMIC 0.18μm工艺搭建整体电路,并使用Spectre对电路进行仿真。仿真结果显示该电路在宽温度范围(-40~125℃)下的频率偏移为0.43%,在1.5~2.5 V电源电压变化范围内,频率变化为0.24%,总电路平均工作电流为19.47μA。

Aiming at the problem of low accuracy of traditional relaxation oscillator,a relaxation oscillator with low power consumption and high stability is designed.The oscillator consists of RC charge-discharge module,active filter module and bias module.A single comparator is used to realize voltage reversal to reduce the overall power consumption,the temperature change is compensated by using a mixture of resistors with opposite temperature characteristics,and the active filter generates voltage feedback to achieve high accuracy of the output clock signal.Using SMIC 0.18μm process to construct the circuit and Spectre is used to simulate the circuit.The simulation results show that the frequency offset of the circuit is 0.43%in the wide temperature range(-40-125℃),the frequency change is 0.24%in the range of 1.5-2.5 V power supply voltage,and the average working current of the circuit is 19.47μA.