A sub-10 nA DC-balanced adaptive stimulator IC with multi-modal sensor for compact electro-acupuncture stimulation

Area of Science:

• Biomedical Engineering
• Neuroscience
• Wearable Technology

Background:

• Electro-acupuncture (EA) is a therapeutic technique combining acupuncture with electrical stimulation.
• Current EA systems often lack portability and real-time feedback mechanisms for adaptive treatment adjustments.
• Monitoring physiological responses during EA is crucial for optimizing therapeutic efficacy and patient safety.

Purpose of the Study:

• To develop a compact, multi-modal feedback electro-acupuncture system for adaptive treatments.
• To integrate electromyography (EMG) and skin temperature sensing for real-time physiological monitoring.
• To enable wireless data transmission and analysis for personalized EA therapy adjustments.

Main Methods:

• A compact EA patch utilizing planar-fashionable circuit board (P-FCB) technology with an adaptive stimulator IC and coin battery.
• Implementation of a closed current loop for single-needle stimulation and measurement of EMG and skin temperature.
• Utilizing a large time constant (LTC) sample and hold (S/H) current matching technique for high-precision charge balancing (<10 nA).
• Wireless data transmission via body channel communication (BCC) to an external EA analyzer.
• A 0.13 μm RF CMOS stimulator chip (12.5 mm²) consuming 6.8 mW at 1.2 V.

Main Results:

• The compact EA system was successfully implemented and tested on human subjects.
• The system demonstrated the capability to measure EMG and skin temperature for analyzing stimulation status.
• High-precision charge balancing (<10 nA) was achieved, ensuring patient safety.
• Wireless transmission of physiological data allowed for real-time analysis of muscle fatigue and skin temperature changes.
• The adaptive stimulator IC supported programmable stimulation current (40 μA-1 mA) with 5 modes and 32 current levels.

Conclusions:

• The proposed compact EA system provides a viable platform for multi-modal feedback-driven, adaptive electro-acupuncture therapy.
• Real-time monitoring of physiological parameters enables practitioners to optimize stimulation parameters for enhanced treatment efficacy.
• The system's compact design and wireless communication facilitate improved patient comfort and treatment personalization.
• This technology holds potential for advancing personalized medicine in electro-acupuncture and related neuromodulation therapies.