CMOS implementation of a programmable attenuation amplifier based on switched capacitors for an optical encoder system

Abstract

Optical encoders are sensors used to measure linear or rotational displacements in industrial and scientific equipment, such as radars, plotters, microscopes, etc. In previous papers our group presented the design of a customized photodetector array for a non-diffractive beam (NDB) optical encoder and the associated electronics. In those works the displacement was sensed by means of a generated photocurrent. In this work we propose a new scheme that uses voltages instead of currents based on a programable gain switched capacitor amplifier. The design was implemented in a standard 0.5μm CMOS process and was characterized using an optical set up.