A mixed-signal IC for multiple cortical stimulation strategies

We present an integrated mixed-signal circuit dedicated for electrical stimulation. The chip has 4 channels using 4 electrodes each, to be connected directly on a square 16-electrode matrix. The circuit is designed for maximum flexibility and safety. It allows stimulation to be monopolar as well as bipolar, and uses a configurable communication protocol, reducing the transfer rate requirements according to the stimulation strategy used. Low power is achieved using dual-voltage supply. Finally, to ensure safe stimulation, characterization and troubleshooting after implantation of the chip, voltage monitoring of any of the 16 electrodes is possible using a rail-to-rail amplifier that can be shut-down for lowest power consumption. The circuit has been fabricated and tested in a CMOS 0.18 /spl mu/m process.