Title :
A four transistor CMOS active pixel sensor with high dynamic range operation
Author :
Lin, Che-l ; Lai, Cheng-Hsiao ; King, Ya-Chin
Author_Institution :
Dept. of Electr. Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
Abstract :
A new CMOS APS using standard CMOS logic technology is proposed to allow high dynamic range operation. The new cell is constructed by incorporating one additional transistor to the conventional three transistor APS. The experimental results demonstrate that extended dynamic range is obtained when operates with a ramped reference voltage source. The cell offers flexible nonlinear transfer characteristics, which can be designed by modifying the operational timing diagram. Furthermore, charge collection on the parasitic capacitor allows for the use of the signal due to hole accumulation. An alternative operation of this cell is also proposed to provide enhanced characteristics in both its sensitivity and dynamic range.
Keywords :
CMOS image sensors; low-power electronics; transfer functions; CMOS active pixel sensor; flexible nonlinear transfer characteristics; four transistor active pixel sensor; high dynamic range operation; hole accumulation; low power consumption; operational timing diagram; parasitic capacitor charge collection; ramped reference voltage source; standard CMOS logic technology; CMOS image sensors; CMOS logic circuits; CMOS technology; Capacitors; Dynamic range; MOSFETs; Photodiodes; Sensor phenomena and characterization; Threshold voltage; Timing;
Conference_Titel :
Advanced System Integrated Circuits 2004. Proceedings of 2004 IEEE Asia-Pacific Conference on
Print_ISBN :
0-7803-8637-X
DOI :
10.1109/APASIC.2004.1349425
