Design of an Energy Harvesting Capable Pixel in 90 nm CMOS Technology Optimized for Implantable Retinal Prosthesis

Abstract

An energy harvesting capable pixel is designed in 90 nm standard complementary metal oxide semiconductor (CMOS) technology with the spectral response optimization considerations. The pixel can perform 2.22 nW power harvesting in 60 klx of illumination per pixel, while the pixel itself consumes 56.26 pW power. Moreover, the pixel could achieve 1.70 μV⁄e− conversion gain and 60.72 dB of dynamic range. The high energy harvesting capability in spite of 90 nm CMOS technology power production limitations is achieved due to triple and dual junctions applications in photosensitive area and floating diffusion regions respectively. In addition, the pixel is engineered to utilize all available pn junctions in energy harvesting mode. It should be noted that, using a triple junction in photosensitive area has enabled spectral response engineering capability, which results in an optimized spectral response of pixel for the spectrums that the human eye exhibits most relative sensitivity (within a spectral range of about 550 nm).