A High-voltage Tolerant and Current-accurate Neural Stimulator Based on A Low-voltage CMOS Process

This article presents a high-voltage Tolerant and current-accurate neural stimulator using smic18 technology and 3.3V deep N-well technology. The circuit is designed with adaptive bias circuit design, and the high voltage tolerance of $6 \times$ VDD is realized by transistor stack technology, which prevents the voltage overload and gate oxide reliability of low voltage transistors. When the DC input voltage is 3.3V, the stimulator can withstand a maximum working voltage of 19.8V. The chip can generate adjustable input stimulation current to match different electrode models, with an output current range of 0-1mA. The mismatch of the biphasic stimulation output current of the stimulator is relatively small, with a mismatch of $0.225 n A$ at $100 u A$ and 2.845nA at 600uA.