Cochlear implant for combined analog and pulsatile electrostimulation of the acoustic nerve

This paper presents a cochlear implant suitable for monopolar stimulation with eight intra-cochlear electrodes. Two independent current sources are implemented, one for stimulation with a broadband analog signal and one for pulsatile stimulation with biphasic current pulses. Possible stimulation modes include purley analog or purley pulsatile stimulation, combined analog and pulsatile stimulation, and up to a maximum pulse repetition rate of 5000 pulses/second continuously interleaved sampling (CIS) stimulation strategies. The implant contains two CMOS-ASICs, one for digital signal processing and one for the implementation of the two current sources. The stimulation current range of the analog channel is 1 μ.A 1 mA, the amplitude of the biphasic pulses can be chosen between 2 μA and 1 mA, pulse duration lies between 50 μs and 400 μs per phase.