具有生物相容性、高精度、宽带、带滞后补偿的改进型 Howland 电流源。
Biocompatible, high precision, wideband, improved Howland current source with lead-lag compensation.
机构信息
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA.
出版信息
IEEE Trans Biomed Circuits Syst. 2013 Feb;7(1):63-70. doi: 10.1109/TBCAS.2012.2199114.
The Howland current pump is a popular bioelectrical circuit, useful for delivering precise electrical currents. In applications requiring high precision delivery of alternating current to biological loads, the output impedance of the Howland is a critical figure of merit that limits the precision of the delivered current when the load changes. We explain the minimum operational amplifier requirements to meet a target precision over a wide bandwidth. We also discuss effective compensation strategies for achieving stability without sacrificing high frequency output impedance. A current source suitable for Electrical Impedance Tomography (EIT) was simulated using a SPICE model, and built to verify stable operation. This current source design had stable output impedance of 3.3 MΩ up to 200 kHz, which provides 80 dB precision for our EIT application. We conclude by noting the difficulty in measuring the output impedance, and advise verifying the plausibility of measurements against theoretical limitations.
豪兰电流泵是一种流行的生物电路，非常适合输送精确的电流。在需要将交流电高精度输送到生物负载的应用中，豪兰的输出阻抗是一个关键的性能指标，它限制了负载变化时输送电流的精度。我们解释了满足宽带宽目标精度的最小运算放大器要求。我们还讨论了在不牺牲高频输出阻抗的情况下实现稳定性的有效补偿策略。使用 SPICE 模型模拟了适用于电阻抗断层成像（EIT）的电流源，并进行了构建以验证稳定运行。该电流源设计的输出阻抗在 200 kHz 时稳定在 3.3 MΩ，为我们的 EIT 应用提供了 80 dB 的精度。最后，我们注意到测量输出阻抗的困难，并建议根据理论限制验证测量的合理性。
Zotero 插件