低成本高输入阻抗前置放大器设计与制作

文档编号:DZXX089  文档字数:9719,页数:26

摘要
 高输入阻抗的放大器的一个非常普遍的用途，是用来放大如加速度计、拾音器等晶体换能器这类传感器的输出信号。这类传感器的内阻抗很高，而输出的信号微弱，因此需要传感器的前置放大器具有高的输入阻抗，才能获取传感器的输出信号。
 在电路设计过程中，常常可以利用自举电容构成的自举电路来改善电路的一些性能指标，比如增大电路的输入阻抗、提高电路的增益以及扩大电路的动态范围等等，本文通过对放大器的基本分析，比较目前各种常见的高输入阻抗放大器及其工作原理，并根据任务要求，提出并制作利用普通四运放和自举电容搭建一低成本的高输入阻抗电路。
 关键词：高输入阻抗，自举电路， 运放
 
  
ABSTRACT
     High input impedance of the amplifier's have very common use, usually they are used to enlarge such as accelerometers, pickups and other crystal transducer output signal of such sensors. Internal impedance of these sensors is high, the output of the signal is weak. Sensor preamplifier should have high input impedance, to obtain the sensor output signal.
     In the circuit design process, often use the bootstrap capacitor bootstrap circuit consisting of a number of performance indicators to improve the circuit, Such as increasing the circuit's input impedance, improve the circuit's gain and expand of the circuit's dynamic range, etc. Based on the amplifier's basic analysis , make comparison of all common high-current amplifier input impedance and working principle. And in accordance with task requirements, put forward and make use of ordinary quad op amp and build a bootstrap capacitor low-cost high input impedance circuit.
  Keywords: High input impedance, Bootstrap circuit, Op amp                   

目录
 
摘要 ................................................................I
ABSTRACT ...........................................................II
第一章 引言 .........................................................1
1.1背景 ............................................................1
1.2 设计内容 .......................................................1
第二章 放大器性能指标及其测试 ......................................2
2.1 开环差模电压放大倍数 ...........................................2
2.2 共模抑制比 .....................................................3
2.3 差模输入电阻 ...................................................4
2.4 失调 ...........................................................4
第三章 高输入阻抗放大器 ............................................6
3.1 输入阻抗的概念 .................................................6
3.2 提高输入阻抗的实用方法 .........................................6
3.2.1输入级加场效应管 ............................................6
3.2.2自举 ........................................................7
第四章 实用高输入阻抗电路设计 ......................................13
4.1放大器的选择 ...................................................13
4.2电路设计 .......................................................15
4.2.1 设计原理总图................................................15
4.2.2 模块分析....................................................15
4.3输入阻抗的测定 .................................................17
致谢 ...............................................................21
参考文献 ...........................................................22
附录：元件清单......................................................23

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