A Fully Programmable Dual-Channel CMOS Neurostimulator With Ultra-Low Charge Mismatch

Electrical neurostimulation is a valid non-pharmacological alternative to drug-based therapies for neurological disorders. Implantable neurostimulators require high flexibility in shaping current pulses and strict charge balancing to avoid tissue and electrode damage. This work presents a fully programmable dual-channel neurostimulator fabricated in 3.3V-180nm CMOS process but fully compliant with higher voltages, up to 9V. The proposed system delivers biphasic or monophasic current pulses with 12-bit amplitude and 8-bit timing resolution and supports up to 16 programmable pulses per channel via SPI/I2C control. Measurements validate on-chip power management, linear DAC-to-current conversion, and reliable generation of user defined pulse trains. Charge mismatch during biphasic stimulation was reduced through calibration from 82.5nC to 6.53nC (0.2%). Results confirm suitability for implantable applications requiring high configurability and reduced charge mismatch.