基于HCPL-7840的小信号隔离变送器  

Small Signal Isolation Transmitter Based on HCPL-7840

作　　者：徐佳[1] 王晓初[1] 张金勋[1] 

机构地区：[1]广东工业大学机械装备制造及控制技术教育部重点实验室,广东广州510090

出　　处：《压电与声光》2011年第4期669-673,共5页Piezoelectrics & Acoustooptics

基　　金：广东省科技计划基金资助项目(2007A010301002)

摘　　要：针对于市面上小信号隔离变送器普遍存在的电路复杂、线性度和抗干扰能力低的现状，用斩波稳零型运算放大器ICL7650、模拟型光电隔离放大器HCPL-7840和通用型运算放大器LM224构成的小信号隔离变送电路，实现了0～75mV的直流输入到0～10V直流输出。用脉宽调制（PWM）集成电路TL494、脉冲变压器和各集成稳压器构成的系统隔离供电电路，实现了输入、输出、电源三方隔离。实验结果表明：该变送器电路简洁，高线性，响应快，隔离效果好，抗干扰能力强，输出信号质量较高，满足小信号采集变送的要求，具有一定的实用性和推广价值。The currently used small-signal isolation transmitters generally have the drawbacks of the circuit complexity, the weakness of the linearity and the anti-interference. A novel small-signal isolation transmitter consisting of the Chopper-stabilized operational amplifier ICL 7650,the analog isolation photo-amplifier HCPL-7840 and the gen eral operational amplifier LM224 was proposed and the DC inputs of 0-75 mV and the DC outputs of 0-10 V have been achieved. An isolated power supply circuit consisting of the pulse width modulation （PWM） IC TL494,pulse transformer and some integrated voltage regulators was used to isolate the three sides of the input, output and the supply. The experimental results showed that the transmitter circuit has the features of concise circuit, high linearity, fast response, good isolation,high anti-interference and high quality of output signals and can satisfy the requirements for the small signalacquisition. The proposed transmitter has certain practicability and is suitable for produc tion.

关 键 词：小信号采集 光电隔离 线性放大 HCPL-7840 TL494 

分 类 号：TH862.1[机械工程—仪器科学与技术]