Balanced Adjustable Mirrored Current Source with Common Mode Feedback and Output Measurement for Bioimpedance...

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Wearable Technology

Background:

• Bioimpedance methods are vital for applications like impedance tomography and electrodermal activity detection.
• Wearable bioimpedance systems require high accuracy and adaptability due to unstable measurement conditions.
• Existing current sources struggle to meet the demands of adaptive bioimpedance systems with varying loads.

Purpose of the Study:

• To develop an improved current source for wearable bioimpedance systems.
• To enhance accuracy and adaptability in bioimpedance measurements for mobile health.
• To overcome limitations of traditional current sources in dynamic environments.

Main Methods:

• Proposed an optimized mirrored architecture for bioimpedance current sources.
• Implemented a common mode feedback system with balanced mirrored sources.
• Validated the design through calculations, SPICE simulations, and complex load measurements.

Main Results:

• Achieved output impedances exceeding 3 MΩ.
• Derived a simplified transconductance function valid up to 1 MHz.
• Demonstrated simple output current adjustment and measurement without additional shunt resistors.

Conclusions:

• The proposed architecture significantly advances accurate wearable bioimpedance acquisition.
• The design offers improved performance for adaptive bioimpedance systems.
• Further optimization of output impedance is possible using generalized impedance converters.