Premium
A 99.95% linearity readout circuit with 72 dB dynamic range for active pixel sensors
Author(s) -
Sá Leonardo Bruno,
Dias Mauricio Henrique Costa,
Dupret Antoine,
Mesquita Filho Antonio Carneiro
Publication year - 2018
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2425
Subject(s) - linearity , dynamic range , wide dynamic range , cmos , sensitivity (control systems) , photodiode , buffer amplifier , high dynamic range , amplifier , electronic circuit , transistor , electronic engineering , voltage , node (physics) , pixel , computer science , electrical engineering , physics , engineering , optoelectronics , computer vision , quantum mechanics
Summary One of the main sources of nonlinearity and sensitivity degradation in conventional active pixel sensor (APS) architectures is the source follower buffer amplifier that isolates the photodiode node from the column bus. To extend the linear region of the output voltage, correct the sensitivity degradation, and improve the imager dynamic range, an output regulated voltage follower is proposed. All these enhancements are achieved without decreasing the pixel fill factor nor increasing the number of transistors and the addressing circuits complexity of a conventional 4T CMOS APS. The performance of the circuit is assessed using a 0.35‐μm CMOS technology. The obtained results show a 14‐dB dynamic range improvement for highly linear applications over the conventional APS readout circuit.