Current source for multifrequency broadband electrical bioimpedance spectroscopy systems. A novel approach

Area of Science:

• Electrical Engineering
• Biomedical Instrumentation
• Bioimpedance Analysis

Background:

• Broadband electrical bioimpedance spectroscopy (EB) is expanding into new clinical applications, requiring higher operating frequencies.
• Accurate EB measurements depend on a stable output current from the analyzer's current source, which necessitates high output impedance across all frequencies.
• Existing voltage-controlled current sources face challenges in maintaining sufficient output impedance at higher frequencies.

Purpose of the Study:

• To propose and validate a novel approach for increasing the output impedance of a common voltage-controlled current source.
• To enhance the performance of current sources for broadband electrical bioimpedance spectroscopy systems.
• To investigate the impact of parasitic capacitances on the proposed circuit's output impedance.

Main Methods:

• A novel circuit design was developed to augment the output impedance of a voltage-controlled current source.
• The proposed circuit was theoretically analyzed.
• The circuit was implemented and experimentally tested to evaluate its performance.

Main Results:

• The implemented circuit demonstrated a clear increment in output impedance.
• The study highlighted the significant influence of parasitic capacitances on the circuit's performance.
• The observed increase in output impedance was less than initially anticipated.

Conclusions:

• The proposed method offers a viable strategy for improving current source output impedance in EB systems.
• Parasitic capacitances present a notable challenge that must be carefully managed in high-frequency EB instrumentation.
• Further optimization is needed to fully realize the potential output impedance enhancement.