JFET高精度可变电阻器的设计及其应用 .pdfVIP

学兔兔 第36卷 第8期 仪 器 仪 表 学 报 V01．36 No．8 2015年8月 Chinese Journal of Scientific Instrument Aug．2015 JFET高精度可变电阻器的设计及其应用：}： 行鸿彦 ，赵 晨 ，余炳莹 ，徐 伟 ’ (1．南京信息工程大学气象灾害预报预警与评估协同创新中心 南京 210044； 2．南京信息工程大学江苏省气象探测与信息处理重点实验室 南京 210044) 摘 要：根据JFET线性区漏源之间沟道电阻受栅源电压控制的机理，推导JFET电流公式，对可变电阻的性能进行了分析。通过 PSpice软件仿真了JFITI1压控可变电阻，提出了改善WET可变电阻非线性及扩展电阻动态范围的方法。结合单片机和D／A转换器， 利用该方法设计了程控JFET可变电阻，其阻值范围为75．703～141．004 Q，分辨率低于0．025 n，满足了自动气象站信号模拟器温度通 道所需电阻阻值范围80．305—130．894 Q及分辨率低于0．03 n的要求，为数据采集器温度通道的检定提供标准的可变电阻信号。 关键词：结型场效应管；压控可变电阻；模拟温度传感器；PSpice 中图分类号：TH811 文献标识码：A 国家标准学科分类代码：510 Design of voltage—controlled resistor based on JFET and its application in automatic weather station signal simulator Xing Hongyan ，Zhao Chen ，Yu Bingying ，Xu Wei ’ (J．Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，№ ng University of Information ScienceTechnology，Na ng 210044，China，China；2．Jiangsu Key Laboratory of Meteorological Observation and Information Processing，Na ng University ofInformation ScienceTechnology，Na ng 210044，China) Abstract：According to the mechanism that the drain—source channel resistance of JFET transistor in the linear region iS controlled by the gate—source voltage，the current formula of JFET is deduced，the performance of the variable resistor is analyzed．The PSpice software is used to simulate the JFET voltage controlled variable resistor，and the method for improving the nonlinearity of the JFET variable resistor and expanding its dynamic range is proposed．Based on above，combining single chip computer and D／A converter with JFET，a pro— grammable JFET