Electrical property modelling of photodiode type CMOS active pixel sensor (APS)
01 Jan 2005-pp 371-375
TL;DR: In this article, the electrical characteristics of photodiode (PD) type CMOS active pixel sensor (APS) pixel were modeled using BSIM3v3 threshold voltage equation for hand calculation with better than 2% peak-to-peak error for full back-gate bias and supply voltages for CMOS process technologies.
Abstract: In this research, few electrical characteristics of photodiode (PD) type CMOS active pixel sensor (APS) pixel were modeled. BSIM3v3 threshold voltage equation was simplified for hand calculation with better than 2% peak-to-peak error for full back-gate bias and supply voltages for CMOS process technologies that has minimum feature sizes between 0.18/spl mu/m and 2.0/spl mu/m. Two fitting function coefficients (FFC) were included in the BSIM threshold model equations for simplification of the equation. FFCs were extracted by using circuit simulation for given process. Using the simplified threshold equation, electrical characteristics of 3T CMOS PD-APS pixel were modeled. Models include; photodiode reset level, pixel amplifier signal range, and pixel reset level boosting factor. Models were evaluated by using wide variety of available CMOS process technologies and compared with the simulation results. Pixel reset level and signal range model equations produce better than 6% and 12% peak-to-peak accuracy with simple hand calculation, respectively. Models were also confirmed with a designed photodiode-type CMOS APS pixel. A CMOS photodiode type APS imager fabricated in a 0.5/spl mu/m, 2P3M, 5Volt CMOS process with 15/spl mu/m square pixel size was used for comparison.
Citations
More filters
TL;DR: A CMOS image sensor capable of imaging and energy harvesting on same focal plane is presented for retinal prosthesis and its efficiency was measured at different light levels.
Abstract: A CMOS image sensor capable of imaging and energy harvesting on same focal plane is presented for retinal prosthesis. The energy harvesting and imaging (EHI) active pixel sensor (APS) imager was designed, fabricated, and tested in a standard 0.5 μm CMOS process. It has 54 × 50 array of 21 × 21 μm2 EHI pixels, 10-bit supply boosted (SB) SAR ADC, and charge pump circuits consuming only 14.25 μW from 1.2 V and running at 7.4 frames per second. The supply boosting technique (SBT) is used in an analog signal chain of the EHI imager. Harvested solar energy on focal plane is stored on an off-chip capacitor with the help of a charge pump circuit with better than 70% efficiency. Energy harvesting efficiency of the EHI pixel was measured at different light levels. It was 9.4% while producing 0.41 V open circuit voltage. The EHI imager delivers 3.35 μW of power was delivered to a resistive load at maximum power point operation. The measured pixel array figure of merit (FoM) was 1.32 pW/frame/pixel while imager figure of merit (iFoM) including whole chip power consumption was 696 fJ/pixel/code for the EHI imager.
46 citations
Cites background from "Electrical property modelling of ph..."
...Signal dependent backgate bias voltage results in the threshold voltage of the pixel transistors (M1-M3) to increase [20]....
[...]
TL;DR: It was shown that the proposed boosted readout does not increase the number of transistors in the 3T CMOS APS pixels nor degrade the image quality, and provides additional 31% dynamic range improvement on top of the seven times (7×) expansion attained by boosting the pixel reset signal.
Abstract: A new pixel readout technique is proposed for three-transistor (3T) CMOS active pixel sensor (APS) pixels. It utilizes the supply-boosting technique (SBT) in order to reduce power consumption and allow ultra low-voltage operation. The pixel supply voltage as well as the pixel reset and select signals were boosted to achieve wider and extended linear operating ranges. A CMOS image sensor containing a 54 × 50 array of 3T CMOS APS pixels was fabricated in a standard 2P3M 5-V 0.5- μm CMOS process to confirm the effectiveness of each boosting operation. Theory, simulation, and measurement results are presented. The boosting pixel supply voltage during pixel readout provides additional 31% dynamic range improvement on top of the seven times (7×) expansion attained by boosting the pixel reset signal. It was shown that the proposed boosted readout does not increase the number of transistors in the 3T CMOS APS pixels nor degrade the image quality.
9 citations
15 May 2011
TL;DR: In order to reduce power consumption and improve low-voltage operation capability of standard three transistor (3T) CMOS active pixel sensor (APS), new pixel readout is proposed utilizing supply boosting technique (SBT).
Abstract: In order to reduce power consumption and improve low-voltage operation capability of standard three transistor (3T) CMOS active pixel sensor (APS), new pixel readout is proposed utilizing supply boosting technique (SBT). Pixel supply voltage as well as reset and select signals for APS pixel are boosted to achieve wider and extended linear operating range in a standard CMOS process with high-Vt transistors. Reset and supply boosting was used for extending dynamic range of the pixel source follower (PSF) amplifier, while the select signal boosting was utilized for linearizing transfer characteristics of the PSF. Extension of PSF dynamic range using reset, select, and supply boosting (RSSB) resulted in operation of 3T APS pixel at 1.2V supply with 150mV dynamic range even though the threshold of the NMOS device was 0.8V. Proposed method does not degrade the device reliability margins and use single supply input.
6 citations
Cites background from "Electrical property modelling of ph..."
...This increase could be as large as 50% of the zero threshold voltage for these devices [12] effecting linear input output characteristics of the PSF....
[...]
01 Dec 2017
TL;DR: In this paper, a new pixel was designed with the capability of imaging and energy harvesting for the retinal prosthesis implant in 0.18µm standard complementary metal oxide Semiconductor technology.
Abstract: A new pixel is designed with the capability of imaging and energy harvesting for the retinal prosthesis implant in 0.18 µm standard Complementary Metal Oxide Semiconductor technology. The pixel conversion gain and dynamic range, are 2.05 $$\upmu{\text{V}}/{\text{e}}^{ - }$$
and 63.2 dB. The power consumption 53.12 pW per pixel while energy harvesting performance is 3.87 nW in 60 klx of illuminance per pixel. These results have been obtained using post layout simulation. In the proposed pixel structure, the high power production capability in energy harvesting mode covers the demanded energy by using all available p-n junction photo generated currents.
4 citations
TL;DR: 4T CMOS APS shown more radiation hardness than the 3T CMos APS and 32 nm technology exhibits lowest radiation-tolerant, indicating 4T has a higher radiation hardness.
Abstract: The widely used CMOS Active Pixel Sensors (APS) in space imaging mission are vulnerable to radiations known as Single Event Transient (SET). This paper focus on 3T and 4T CMOS APS with tech...
3 citations
Cites methods from "Electrical property modelling of ph..."
...This AC source is used by assuming the light is continuously hitting this photo-detector at a constant period (Ay 2005)....
[...]
References
More filters
05 Dec 1993
TL;DR: In this article, the Philips MOS MODEL 9 is presented for the successful confrontation with analog requirements, the scaling of parameters with geometry, the accuracy of the model over the whole geometry range of a process, its capabilities in the description of various processes at least down to 0.35 /spl mu/m and a comparison with advanced analog models available in commercial circuit simulators.
Abstract: Analog applications of MOS transistors in integrated circuits impose enhanced requirements on the compact MOS models used in circuit simulators. Here we present for the Philips MOS MODEL 9 the successful confrontation with these analog requirements, the scaling of parameters with geometry, the accuracy of the model over the whole geometry range of a process, its capabilities in the description of various processes at least down to 0.35 /spl mu/m and a comparison with advanced analog models available in commercial circuit simulators. >
41 citations
TL;DR: A 512×512 CMOS active pixel sensor (APS) was designed, fabricate, and tested for frontside illumination suitable for use in astronomy specifically in telescope guider systems as a replacement of CCD chips as mentioned in this paper.
Abstract: A 512×512 CMOS Active Pixel Sensor (APS) imager has been designed, fabricate, and tested for frontside illumination suitable for use in astronomy specifically in telescope guider systems as a replacement of CCD chips. The imager features a high-speed differential analog readout, 15 μm pixel pitch, 75 % fill factor (FF), 62 dB dynamic range, 315Ke- pixel capacity, less than 0.25% fixed pattern noise (FPN), 45 dB signal to noise ratio (SNR) and frame rate of up to 40 FPS. Design was implemented in a standard 0.5 μm CMOS process technology consuming less than 200mWatts on a single 5 Volt power supply.
CMOS Active Pixel Sensor (APS) imager was developed with pixel structure suitable for both frontside and backside illumination holding large number of electron in relatively small pixel pitch of 15 μm. High-speed readout and signal processing circuits were designed to achieve low fixed pattern noise (FPN) and non-uniformity to provide CCD-like analog outputs. Target spectrum range of operation for the imager is in near ultraviolet (300-400 nm) with high quantum efficiency. This device is going to be used as a test vehicle to develop backside-thinning process.
13 citations
"Electrical property modelling of ph..." refers background in this paper
...Other parameters of the imager were reported in [6]....
[...]