Design of Electrical Stimulation Circuit in 180 nm/1.8 V Standard CMOS Process

This article presents an electrical stimulation circuit for use in implantable medical microsystems, which includes digital-to-analog converter, tuned cascade transistor structure, voltage level shifter circuit, and switches circuit for driving the stimulation current. In this research, DAC circuits and current directing switches are proposed in 180nm CMOS 1.8 V technology. Among the performed works, we can mention the increase of the current range up to 2.5 milliamperes and the stimulation voltage up to 12.6 volts to stimulate high-quality nerve tissues. In this context, a digital-to-analog converter circuit with a thermometer-coded structure has been designed and simulated with INL, DNL<0.5 LSB specifications, as well as SFDR=50.74 dB, SNDR=37.1 dB, and ENOB=5.87 Bits. Moreover the most critical parameter of the final system is the measured power consumption of 1.23 milliwatts.