Pseudo-Resistor Based Attenuator as an Efficient Electrode Driver for Sinusoidal Stimulation of Retinas

Most concepts for retinal stimulation rely on rectangular waveforms, although studies suggest sinusoidal stimulation might improve visual perception. We present a novel approach for a power and area efficient generation of sinusoidal stimulation waveforms by modulation of an external reference sine wave. Modulation is performed by an attenuator based on variable CMOS pseudo-resistors. The implementation of a complete channel is presented along with two different versions of the attenuators. Both architectures are investigated in terms of signal quality, symmetry and power consumption.