一种低温漂张弛振荡器设计  

Design of a Low Temperature Drift Relaxation Oscillator

作　　者：危林峰 李文昌[1,2] 尹韬 刘剑 张天一[1] Wei Linfeng;Li Wenchang;Yin Tao;Liu Jian;Zhang Tianyi(Institute of Semiconductors,ChineseAcademyof Sciences,Beijing 100083,China;College of Materials Science and Opto-Electronic Technology,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院半导体研究所,北京100083 [2]中国科学院大学材料科学与光电技术学院,北京100049

出　　处：《半导体技术》2023年第1期31-36,72,共7页Semiconductor Technology

基　　金：国家自然科学基金资助项目(61974146)。

摘　　要：针对传统张弛振荡器输出频率的稳定性易受温度影响的问题,设计了一种结构简单的低温漂张弛振荡器。将MOS管的阈值电压作为参考比较电压,无需考虑比较器偏移电压的影响,偏置电流电路提供与阈值电压有关的电容充电电流,可以抵消参考比较电压温度系数对振荡器输出频率的影响,最终使其对温度的稳定性只受电阻温漂的影响。设计中电阻采用相反温度系数的串/并联复合的拓扑结构,能有效降低电阻温漂对输出频率温度稳定性的影响。该振荡器采用0.35μm BCD工艺实现,已集成应用于一款温度传感芯片,振荡器单元尺寸为0.25 mm×0.3 mm,电源电压为3.3 V,功耗约为15μW。测试结果表明,当电源电压在3~3.6 V变化时,输出频率变化小于0.34%;当温度从-55℃变化到125℃时,输出频率的温度系数为83.6×10^(-6)/℃。Aiming at the problem that the output frequency stability of the traditional relaxation oscillator was easily affected by temperature,a low temperature drift relaxation oscillator with a simple structure was designed.The threshold voltage of the MOS transistor was used as the reference comparison voltage,without considering the influence of the comparator offset voltage.The bias current circuit provides a capacitor charging current related to the threshold voltage,which can eliminate the influence of the temperature coefficient of the reference comparison voltage on the oscillator output frequency,and finally make the stability of the temperature be only affected by the temperature drift of the resistance.The resistor topology of series/parallel combination with opposite temperature coefficients was adopted in the design,which can effectively reduce the influence of the temperature drift of the resistors on the temperature stability of the output frequency.The oscillator was realized by using 0.35μm BCD process and had been integrated into a temperature sensing chip.The size of the oscillator unit is 0.25 mm×0.3 mm.The supply voltage is 3.3 V,and the power consumption is about 15μW.The test results show that when the power supply voltage changes from 3 V to 3.6 V,the output frequency changes less than 0.34%.When the temperature changes from-55℃to 125℃,the temperature coefficient of the output frequency is 83.6×10^(-6)/℃.

关 键 词：张弛振荡器 低温漂 并/串联复合电阻 阈值电压 比较器 

分 类 号：TN43[电子电信—微电子学与固体电子学] TN753.8