低功耗低温漂的RC张弛振荡器

Low-power low-temperature drift RC relaxation oscillation

针对在物联网设备中使用的电阻电容(RC)张弛振荡器低功耗低温漂的需求,通过将RC张弛振荡器中的参考电压产生电路和自偏置电流产生电路复合使用,简化电路结构,减小供电电压和偏置电流,降低电路的功耗.采用水平级联的共栅共源结构、反相器链及时钟电压自举结构,减少温度变化对延时及振荡频率的影响.采用串并联电阻网络减少因电阻工艺偏差导致的影响,并将该电阻网络配置成正温度特性,以平衡RC时间常数和比较器延时的温度依赖性,提高振荡频率的温度稳定性.仿真结果表明:本文RC张弛振荡器的振荡频率为1.2 kHz,功耗和温漂系数分别为1.351 nW和139×10^(-6)/℃,与典型RC张弛振荡器相比,其功耗和温漂性能均有显著的提升.

Aiming at the requirement of low power consumption and low temperature drift of resistance-capacitance(RC)relaxation oscillation used in internet of things devices,the reference voltage generating circuit and self-bias current generating circuit were combined,and the circuit structure was simplified with enough small supply voltage and bias current used in RC relaxation oscillation to reduce power dissipation.The cascade common gate and common source structure,the inverter chain and the clock voltage booster were utilized to reduce the influence of temperature variation to the delay and oscillation frequency.The series and parallel resistor network was employed to reduce the influence due to process deviation of resistors,and the network was configured into positive temperature characteristics on purpose of balancing the temperature dependence of RC time constant and comparator delay to improve the temperature stability of oscillation frequency.The simulation results show that the oscillation frequency of the RC relaxation oscillation is 1.2 kHz,and the power consumption and the temperature drift are 1.351 nW and 139×10^(-6)/℃respectively,which explains significantly improved performances such as power consumption and temperature drift coefficient than that of the typical RC relaxation oscillation.