Comprehensive study of Howland circuit with non-ideal components to design high performance current pumps
Comprehensive study of Howland circuit with non-ideal components to design high performance current pumps
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DOI：
10.1016/j.measurement.2015.12.044
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发表时间：
2016-03
期刊：
影响因子：
5.6
通讯作者：
A. Mahnam;Hassan Yazdanian;M. M. Samani-M.
中科院分区：
文献类型：
--
作者：
A. Mahnam;Hassan Yazdanian;M. M. Samani-M.
Howland电路是一种流行的高性能压控电流泵，它可以吸收和产生精确的电流量，并提供高输出阻抗和高频带宽。本文推导了非理想Howland电流泵性能特性的解析表达式，结果表明，主要特性可以通过三个独立的参数来调节：电阻器的刻度、反馈比和电流传感电阻器的值。通过计算机仿真对推导出的公式进行了评估，并以心阻抗心动图系统中的电流泵为例进行了设计。在仿真和实验测试的基础上，对该电路的性能进行了评估，并与文献中已有的几种设计进行了比较。这些关系为分析Howland电流泵的不同配置提供了一个统一的框架，并可以针对具有特定性能要求的不同应用促进其设计过程。
Howland circuit is a popular high performance, voltage-controlled current pump, which can both sink and source precise amounts of current and provide high output impedance as well as high frequency bandwidth. In this article, analytical expressions are derived for performance characteristics of non-ideal Howland Current Pump, and it is shown that the main characteristics can be adjusted using three independent parameters: resistors’ scale, feedback ratio, and current sensing resistor’s value. The derived expressions are evaluated by computer simulations, and then are used to design a current pump for an impedance cardiography system, as an example. Performance of the circuit is evaluated based on simulations and experimental tests, and then is compared with several previous designs in the literature. The relationships provide a unified framework for the analysis of different configurations of Howland current pump and can facilitate its design process for different applications with specific performance requirements.