A Low Dark Current 160 dB Logarithmic Pixel with Low Voltage Photodiode Biasing

Brunetti, Alessandro Michel; Choubey, Bhaskar

doi:10.3390/electronics10091096

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…Additionally, for lowlight imaging applications, a linear-logarithmic counter in a high-dynamic-range image sensor enables user-programmable sensitivity modification [32]. Furthermore, a logarithmic pixel design, achieved by utilizing a low-voltage photodiode bias to reduce dark current, enhances dynamic range and dark responsiveness [33]. In intelligent sensor networks, employing the maximum logarithm message transmission technique preserves precision and efficiency, while simultaneously reducing the complexity of multinode detection.…”

Section: Discussionmentioning

confidence: 99%

Using Optical Sensor Applied to Rapid Soil Test Kit for NH4+ and NO3- in Soil

Jaisin,

Aumtong,

Chotamonsak

2024

Preprint

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This study aims to construct simple devices to ascertain the concentrations of ammonium (NH4+) and nitrate (NO3-). The device structure comprises a visible and near-infrared absorption meas-urement room, along with an RGB (red, green, and blue) absorption measurement room, con-stituting the two measuring rooms. Both the measurement rooms are equipped with light sources and detectors configured to operate in opposed or thru-beam modes. A tiny processor is utilized for processing the measurements, with an algorithm implemented within its memory. During the algorithm development phase, ranges for measuring the quantity of nutrients were categorized using a discriminant analysis approach. Thirty percent of the soil sample data were utilized as verification data, while the remaining 70 percent served as training data. Nutrient content values from reliable measuring instruments were incorporated into all datasets. Discriminant analysis was employed to classify the amount of NH4+ into five ranges based on the test results. When tested with soil samples, the accuracy was 66.13% compared to the reference value of a reliable measuring device. Similarly, NO3- was classified into four ranges with an accuracy of 81% com-pared to the reference value of a reliable measuring device.

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Section: Discussionmentioning

confidence: 99%

Using Optical Sensor Applied to Rapid Soil Test Kit for NH4+ and NO3- in Soil

Jaisin,

Aumtong,

Chotamonsak

2024

Preprint

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show abstract

“…Figure 11b illustrates the second type of pixel, i.e., the active pixel sensor (APS) [65,[81][82][83][84][85][86][87], which consists of a matrix of pixels in the same way as the PPS, but with the difference of containing three MOSFETs, where M 1 is the reset transistor, M 2 is the amplifying transistor, and M 3 is the pixel address transistor. The APS has three modes of operation: the reset mode, the integration mode, and the readout mode [12,22,35,[88][89][90]. The reset signal closes the reset transistor M 1 during the first mode and directly connects the N-type region of the photodetector to the supply voltage V dd .…”

Section: Architectures 41 Photocurrent Integrationmentioning

confidence: 99%

A Review of Optical Sensors in CMOS

Gounella,

Ferreira,

Amorim

et al. 2024

Electronics

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This paper presents an overview of silicon-based optical sensors for the measurement of light in the visible spectrum range. The review is focused on sensors based on CMOS (complementary metal-oxide semiconductor) technology due to the high availability, low cost, ease of prototyping, and well-established fabrication processes. CMOS technology allows integration with the CMOS readout and control electronics in the same microdevice, featuring high-volume fabrication with high-reproducibility and low-cost. This review starts with an explanation of the phenomena behind opto-electronic transduction. It also presents and describes the most common components responsible for optical transduction, readout electronics, and their main characteristics. This review finishes with the presentation of selected applications to grasp where and how these sensors can be used.

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“…To better display the image, many commercial photography devices have a non-linear response to light intensity [ 2 ]. Non-linearity is intentionally implemented for purposes like high-dynamic-range image sensors [ 3 , 4 ], or to match human visual perception [ 5 ]. But for accurate measurements, like in some medical and scientific imaging fields, optical sensors require precise light intensity and frequency responses [ 6 ], where the linearity of the sensor becomes an important parameter.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Pixel Design and Operation Conditions on Linear Output Range of 4T CMOS Image Sensors

Zhang,

Xu,

Cheng

2024

Sensors

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We analyze several factors that affect the linear output range of CMOS image sensors, including charge transfer time, reset transistor supply voltage, the capacitance of integration capacitor, the n-well doping of the pinned photodiode (PPD) and the output buffer. The test chips are fabricated with 0.18 μm CMOS image sensor (CIS) process and comprise six channels. Channels B1 and B2 are 10 μm pixels and channels B3–B6 are 20 μm pixels, with corresponding pixel arrays of 1 × 2560 and 1 × 1280 respectively. The floating diffusion (FD) capacitance varies from 10 fF to 23.3 fF, and two different designs were employed for the n-well doping in PPD. The experimental results indicate that optimizing the FD capacitance and PPD design can enhance the linear output range by 37% and 32%, respectively. For larger pixel sizes, extending the transfer gate (TG) sampling time leads to an increase of over 60% in the linear output range. Furthermore, optimizing the design of the output buffer can alleviate restrictions on the linear output range. The lower reset voltage for noise reduction does not exhibit a significant impact on the linear output range. Furthermore, these methods can enhance the linear output range without significantly amplifying the readout noise. These findings indicate that the linear output range of pixels is not only influenced by pixel design but also by operational conditions. Finally, we conducted a detailed analysis of the impact of PPD n-well doping concentration and TG sampling time on the linear output range. This provides designers with a clear understanding of how nonlinearity is introduced into pixels, offering valuable insight in the design of highly linear pixels.

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A Low Dark Current 160 dB Logarithmic Pixel with Low Voltage Photodiode Biasing

Cited by 5 publications

References 26 publications

Using Optical Sensor Applied to Rapid Soil Test Kit for NH4+ and NO3- in Soil

Using Optical Sensor Applied to Rapid Soil Test Kit for NH4+ and NO3- in Soil

A Review of Optical Sensors in CMOS

The Effect of Pixel Design and Operation Conditions on Linear Output Range of 4T CMOS Image Sensors

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