A Low Area and Low Power Pulse Width Modulation Based Digital Pixel Sensor

Abstract

A novel low power and low area Digital Pixel Sensor using Pulse Width Modulation technique is designed in one-poly six-metal 0.18μm CMOS standard technology. The pixel has a pitch of 18.33 μm and a fill factor of about 24%. The Light to Time Converter (LTC) at the core of the pixel consumes only 5.5% of the pixel area. Post-layout simulation results exhibit 90.85 dB dynamic range, total power consumption of about 853.65 pW at 33 frames per second and a short conversion time with a maximum of 23.25 ms. The pixel’s digital output is linearized by using a look-up table based digital linearization circuitry resulting in a root mean square pixel-wise error of 0.797 between the original and the captured images. Monte Carlo analysis shows 2.93% Fixed Pattern Noise for the pixel.