A Programmable 6 bit DAC of current-steering dedicated to nerve stimulator

In this article we present a programmable current source architecture based on nine bits to modulate the charge quantity injected in the cochlear nerve ending. Our architecture is designed from a portable system to cochlear implant. In fact, the proposed architecture must be flexible and allows a transparency via the stimulation algorithms in order to satisfy the different pathological cases. The architecture which based on thermometer digital to analog converter presents a good linearity. As well, it is capable to generate a maximum current about 1 mA through a 1 KOmega [1, 2] load, which is around the typical nerve impedance. The DAC currents sources have been seized to minimize power consumption, to reduce silicon occupation and to offer a worse case error around 0.08LSB differential linearity error and 0.4LSB integral linearity. This device is designed with a 0.35mum CMOS technology.