Implantable stimulator and recording device for artificial prosthesis control

This paper presents an application-specific integrated circuit (ASIC) consisting of both, a four-channel neural stimulator and a single-channel recording amplifier, along with their digital control and regulated voltage supplies. The ASIC has been designed to be compatible with different types of electrodes although the use of sieve electrodes was considered a priority. The main performances of this ASIC as stimulator are: fully programmability for several stimuli shapes (monophasic, biphasic, arbitrary amplitude/duration pairs for stimulation and recovery phases), wide frequency range (7 Hz to more than 350 Hz with 1 Hz resolution) and high-current range (>1.5mA in two scales, with 6 bits resolution). Furthermore, any anode can be associated with any cathode, thus improving the spatial selectivity of some electrode types. From the recording viewpoint, the ASIC exhibits very low noise (5nV/Hz), high CMRR (94 dB) and digitally programmable gain and bandwidth. The overall digital control is designed to control up to 16 stimulation channels and four recording amplifiers using a regular and modular implementation for the analog parts which gives rise to higher ASIC performances with a small increase in area. The system has been integrated using high voltage CMOS 0.7μm technology. “In vitro” experimental results are also presented.