A 120-dB Dynamic Range CMOS Image Sensor With Programmable Power Responsivity

• Published in: IEEE journal of solid-state circuits Vol. 42; no. 7; pp. 1555 - 1563
• Main Authors: Stoppa, D., Vatteroni, M., Covi, D., Baschirotto, A., Sartori, A., Simoni, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.07.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Arrays; Calibration; CMOS; CMOS active pixel; CMOS image sensors; CMOS technology; Design. Technologies. Operation analysis. Testing; Digital cameras; Dynamic range; Electronics; Exact sciences and technology; General equipment and techniques; Image sampling; image sensor; Image sensors; Imaging devices; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Integrated circuits; Integrated circuits by function (including memories and processors); Layout; Noise; Noise generators; Physics; Pixel; pixel architecture; Pixels; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; video camera; pixel architecture; Measurement sensor; CMOS image sensors; Video cameras; dynamic range; video camera; Irradiance; Smart pixels; Response function; Complementary MOS technology; Integrated circuit; Distance measurement; CMOS active pixel; Comparator circuit; Image sensor; Analog memory; digital cameras
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2007.899089

A high dynamic range CMOS image sensor providing a user-programmable power responsivity curve is presented. Each pixel integrates, besides a 4T active pixel structure, a voltage comparator and an analog memory to implement a time-to-saturation scheme while also providing the standard integrated photo-current signal. The sensor generates two 10-bit analog outputs allowing a typical dynamic range exceeding 120 dB with a temporal noise lower than 0.13% and a fixed pattern noise of 0.4% (1.7%) of the total signal swing (2 V) at low (high) irradiance without any external calibration procedures. A 140 times 140-pixel array has been fabricated in a 0.35-mum, two-poly four-metal (2P4M), 3.3-V standard CMOS technology. The chip measures 3.9 times 4.6 mm 2 with a pixel pitch of 15 mum and a fill factor of 20%.