A High-Precision Electrical Stimulator ASIC with Adaptive Charge Balancing for Long-Term Implantable Neuromodulation

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering

Background:

• Neuromodulators are crucial for treating neurological disorders and improving patient quality of life.
• Long-term use of implanted neuromodulators presents challenges in therapeutic efficacy and safety.

Purpose of the Study:

• To enhance therapeutic efficacy and address safety concerns of long-term implanted neuromodulators.
• To develop high-performance techniques for improved neuromodulation.

Main Methods:

• Developed a novel redundant current mapping (RCM) technology for enhanced stimulation resolution.
• Implemented a power-efficient self-adaptive pulse-width calibration (SAPCA) charge-balancing (CB) scheme for long-term safety.
• Integrated compliance-extension techniques to achieve a voltage compliance of ±11 V.

Main Results:

• Fabricated an ASIC in a 180-nm Bipolar-CMOS-DMOS (BCD) process with an area of 0.285 mm²/ch.
• Achieved 14.5-bit resolution over a 6.5-mA current range and 12.8-bit resolution over a 10-mA current range.
• Reduced residual voltage (Vres) to ±5 mV with minimal power consumption (1.74 μW) and demonstrated sustained CB in vivo.

Conclusions:

• The developed ASIC significantly improves stimulation resolution and power efficiency.
• The novel SAPCA CB scheme ensures long-term safety and reliability for chronic neuromodulation.
• This work presents a high-performance neuromodulator solution addressing key challenges in current technology.