Title :
A numerical analysis of a CMOS image sensor with a simple fixed-pattern-noise-reduction technology
Author :
Yonemoto, Kazuya ; Sumi, Hirofumi
Author_Institution :
Dept. of Electron., Inf. & Commun. Eng., Waseda Univ., Tokyo, Japan
fDate :
5/1/2002 12:00:00 AM
Abstract :
A 1/3-in 640×480-pixel CMOS image sensor with a simple fixed-pattern noise-reduction technology with a five-transistor pixel circuit and a low input-voltage current-voltage (I-V) converter was previously developed. In this report, we show that the low-input-voltage I-V converter with a current-mirror circuit improves the amplification factor and linearity of the pixel circuit. In a five-transistor pixel circuit, the threshold voltage of the X-Y addressing transistor affects the amplitude and the level of the readout pulse. An analysis of the mechanism of the X-Y addressing transistor shows the basic concept behind the selection of the threshold voltage. An L-shaped readout gate for a pinned photodiode is compared with a straight readout gate, and is proved to be adequate for rapid charge transfer
Keywords :
CMOS image sensors; current mirrors; image sampling; integrated circuit noise; interference suppression; numerical analysis; readout electronics; 0.33 in; 0.35 micron; 307200 pixel; 480 pixel; 640 pixel; CMOS image sensor; L-shaped readout gate; X-Y addressing transistor; active pixel sensor; amplification factor; correlated double sampling; current-mirror circuit; five-transistor pixel circuit; fixed-pattern-noise-reduction technology; hole accumulation diode; image lag; low input-voltage current-voltage converter; numerical analysis; pinned photodiode; pixel circuit linearity; rapid charge transfer; readout pulse amplitude; readout pulse level; straight readout gate; threshold voltage; CMOS image sensors; CMOS technology; Circuit noise; Image converters; Linearity; Numerical analysis; Pixel; Pulse amplifiers; Pulse circuits; Threshold voltage;
Journal_Title :
Electron Devices, IEEE Transactions on
