Programmable Current Source Design Dedicated to an Advanced Cochlear Implant Micro-Stimulator

摘要

We propose this paper concerns study and conception of a programmable current source design that would operate a micro-stimulator, the mere part of an advanced cochlear implant. Such architecture requires a current source permitting to generate multiform bidirectional current pulses useful for cochlea's stimulation. Besides, thanks to a convivial and programmable electronic module, flexibility was provided in current pulses generation. In fact, the stimulation threshold could be determined using 3-bits for the Digital to Analog converter 'DAC in order to fix the maximum convenient comfortable stimulation. Then, within a current stimulation range i.e., stimulation threshold to comfortable stimulation, the stimulation current pulses could be controlled in amplitude as well as in width by using a 6-bits thermometer DAC. These parameters permit to modulate the charge quantity to be injected later in the cochlea's nerve endings. The current sources of the 6-bits DAC have been sized with great optimization in order to guaranty low power consumption, low silicon occupation, an INL less than 0.4 LSB and a DNL less than 0.08 LSB. The maximum stimulation current output provided was about 1 mA of full scale current at each output using 3.3 V supply, when an output load was estimated to 1 Kft.