A 16-Channel Neurostimulation IC With Self-Biased Monopolar Stimulus Drivers and a Multiple-Output Charge-Pump Converter Achieving 25.44-mW/mm2 Power Density in Low-Voltage CMOS

Electrical neuromodulation has shown superior therapeutic outcomes compared with pharmacological interventions alone. This work introduces a 16-channel neurostimulation IC featuring transistor-stacked monopolar stimulation drivers in standard CMOS technology. With a self-adaptive biasing scheme, the stimulation driver ensures operational safety across all load conditions under the ±6-V voltage compliance and successfully addresses potential leakage issues in prior work. Each driver features 8-bit current control with $1~\mu $ A resolution. An on-chip charge-pump system generates ±6-V supplies using a novel multiple-output pulse-skipping modulation scheme and achieves a remarkable power density of 25.44 mW/mm² through the systematic optimization of sub-converters. The 16-channel neurostimulation IC is fabricated in a 180-nm standard CMOS technology, occupying a total pad-included area of 3 mm². The compactness and process compatibility of the design demonstrate the potential for enabling next-generation high-channel-count neural interfaces.