Design of a reconfigurable stimulator for multichannel integrated systems dedicated to neurobiology experiments

This paper presents the design and simulation results of a reconfigurable stimulator dedicated to multichannel neurobiology experiments. The proposed circuit employs a bipolar current stimulation and is based on only one operational amplifier that is dynamically switched among anodic and cathodic phases. The both multibiasing and current reusing techniques are used to save power consumption and area occupation of the stimulator. Additionally, the special attention was paid to increase the voltage compliance of the circuit what resulted in 91% of the voltage supply voltage compliance while keeping high output impedance in tens of mega-ohm range. The main current stimulator parameters, i.e. the current polarity and its value, duration and frequency of the current pulses, are controlled digitally. Each of the three current ranges, i.e. 2 μA, 10 μA, 200 μA, are controlled with 5-bit resolution. To keep the current pulses uniformity from channel to channel at a high level the MOS body biasing is used. The current stimulator is supplied from 3.3 V and is designed in CMOS 180 nm.