脑电检测前置放大器静电保护电路的设计  

Design of the electrostatic protection circuit for EEG detection preamplifier

作　　者：王敏[1] 陈亚光[2] 

机构地区：[1]武昌理工学院信息工程学院,湖北武汉430223 [2]中南民族大学生物医学工程学院,湖北武汉430074

出　　处：《电子技术应用》2013年第7期80-82,共3页Application of Electronic Technique

基　　金：国家自然科学基金(30370397)

摘　　要：以CMOS仪表运算放大器作为脑电检测前置放大器是经常选择的技术方案。但是,在使用过程中人体静电所产生的高能电子流会击穿COMS管的绝缘栅并停留在那里,从而使得放大器无法正常工作。采用在输入回路中并接二极管或电容器的方法可以实现静电保护,但由于器件参数的不对称性将极大地降低系统的共模抑制比。为此设计了一个有源储能电路,通过该电路能精密调节等效电容量的大小,在不影响共模抑制比的前提下,提高了放大器的抗静电能力,增强了系统的可靠性。Using CMOS instrumentation amplifier as the preamplifier of EEG detection is often technical solutions. However, CMOS device is very sensitive to the static electricity. When the COMS component is used as preamplifier,the enormous energy electron stream from human body static electricity will breakdown COMS tube insulated gate and stay there, making the amplifier does not work. Commonly, the capacitor can be used to form an electrostatic protection circuit, But this will reduce the CMRR,tbr it is very difficult to adjust the balance of two capacitors in wide range.To solve this problem, We have designed an active tank circuit that can fine adjust the size of the equivalent capacitance. Under the premise does not affect CMRR and improve the anti- static electricity ability of the amplifier, and enhance the reliability of the system.

关 键 词：CMOS仪表放大器 静电保护 有源电容 

分 类 号：TN722[电子电信—电路与系统]