A multichannel neurostimulator with transcutaneous closed-loop power control and self-adaptive supply

This paper presents an integrated multichannel neurostimulator ASIC with improved power management efficiency. The stimulator features transcutaneous closed-loop power control that enables optimum power transfer in spite of the coupling variation as well as the variation in the stimulation threshold/current. A programmable adaptive supply in the high voltage (HV) domain is further proposed to minimize the power dissipation during the active stimulation mode in terms of stimulus current/electrode impedance inconsistencies. The stimulator prototype, including the power management, the digital control as well as a 16 channel stimulation frontend, is fabricated in AMS 0.35μm HV CMOS technology. In measurements, automatic supply voltage adaptation from 13.1V to 8V with running stimulations has been achieved, resulting in maximum power saving of 40% for the implantable circuit.