An 8-Channel 9-V-Compliant Crosstalk-Free Bipolar Biphasic Current-Controlled Neural Stimulator in a Standard CMOS Technology

An 8-channel bipolar biphasic current-controlled stimulation IC based on a low-voltage standard CMOS technology is presented in this brief. The stimulation IC features the voltage compliance of as much as 9 V through transistor-stacking and achieves reliable operation regardless of the load impedances. The proposed design allows simultaneous multi-channel stimulation without inter-channel crosstalks. A serial peripheral interface (SPI) is employed to program the IC. Seven magnitude levels of the stimulation current from 10~\mu \text{A} to 70~\mu \text{A} can be generated with an inaccuracy of only 1.73%. The IC is fabricated in a 0.18- \mu \text{m} 1.8-V/3.3-V standard CMOS process with each stimulation channel of a compact size. A head-stage including the IC and electrodes along with a custom-designed software user-interface is demonstrated with measurement results.