• Title, Summary, Keyword: Wide dynamic range

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Wide Dynamic Range CMOS Image Sensor with Adjustable Sensitivity Using Cascode MOSFET and Inverter

  • Seong, Donghyun;Choi, Byoung-Soo;Kim, Sang-Hwan;Lee, Jimin;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.27 no.3
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    • pp.160-164
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    • 2018
  • In this paper, a wide dynamic range complementary metal-oxide-semiconductor (CMOS) image sensor with the adjustable sensitivity by using cascode metal-oxide-semiconductor field-effect transistor (MOSFET) and inverter is proposed. The characteristics of the CMOS image sensor were analyzed through experimental results. The proposed active pixel sensor consists of eight transistors operated under various light intensity conditions. The cascode MOSFET is operated as the constant current source. The current generated from the cascode MOSFET varies with the light intensity. The proposed CMOS image sensor has wide dynamic range under the high illumination owing to logarithmic response to the light intensity. In the proposed active pixel sensor, a CMOS inverter is added. The role of the CMOS inverter is to determine either the conventional mode or the wide dynamic range mode. The cascode MOSFET let the current flow the current if the CMOS inverter is turned on. The number of pixels is $140(H){\times}180(V)$ and the CMOS image sensor architecture is composed of a pixel array, multiplexer (MUX), shift registers, and biasing circuits. The sensor was fabricated using $0.35{\mu}m$ 2-poly 4-metal CMOS standard process.

Study about Integration Time Control for Wide Dynamic Range in Image Capture Device (Wide Dynamic Range를 얻기 위한 이미지 촬상 장치의 Integration Time Control에 관한 연구)

  • Um, Kyu-Hoi;Lee, Sang-Jin;Im, Na-Ri;Choi, Byung-Sun
    • Proceedings of the IEEK Conference
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    • pp.273-274
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    • 2007
  • 영상 신호에서 Dynamic Range는 이미지가 포함하고 있는 휘도의 최소 레벨과 최대 레벨의 비이다. 이미지 촬상 장치가 표현할 수 있는 Dynamic Range는 한정되어 있기 때문에 한정된 범위를 벗어나는 영역에 대해서는 이미지의 왜곡 혹은 손실이 발생한다. 본 논문에서는 Line별로 다른 Integration Time을 적용하는 방법으로 영상의 계조 표현 범위를 넓게 향상시켜 Wide Dynamic Range를 갖는 영상을 얻는 방법을 기술한다.

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Dual-Sensitivity Mode CMOS Image Sensor for Wide Dynamic Range Using Column Capacitors

  • Lee, Sanggwon;Bae, Myunghan;Choi, Byoung-Soo;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.26 no.2
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    • pp.85-90
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    • 2017
  • A wide dynamic range (WDR) CMOS image sensor (CIS) was developed with a specialized readout architecture for realizing high-sensitivity (HS) and low-sensitivity (LS) reading modes. The proposed pixel is basically a three-transistor (3T) active pixel sensor (APS) structure with an additional transistor. In the developed WDR CIS, only one mode between the HS mode for relatively weak light intensity and the LS mode for the strong light intensity is activated by an external controlling signal, and then the selected signal is read through each column-parallel readout circuit. The LS mode is implemented with the column capacitors and a feedback structure for adjusting column capacitor size. In particular, the feedback circuit makes it possible to change the column node capacitance automatically by using the incident light intensity. As a result, the proposed CIS achieved a wide dynamic range of 94 dB by synthesizing output signals from both modes. The prototype CIS is implemented with $0.18-{\mu}m$ 1-poly 6-metal (1P6M) standard CMOS technology, and the number of effective pixels is 176 (H) ${\times}$ 144 (V).

CMOS Image Sensor with Dual-Sensitivity Photodiodes and Switching Circuitfor Wide Dynamic Range Operation

  • Lee, Jimin;Choi, Byoung-Soo;Bae, Myunghan;Kim, Sang-Hwan;Oh, Chang-Woo;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.26 no.4
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    • pp.223-227
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    • 2017
  • Conventional CMOS image sensors (CISs) have a trade-off relationship between dynamic range and sensitivity. In addition, their sensitivity is determined by the photodiode capacitance. In this paper, CISs that consist of dual-sensitivity photodiodes in a unit pixel are proposed for achieving wide dynamic ranges. In the proposed CIS, signal charges are generated in the dual photodiodes during integration, and these generated signal charges are accumulated in the floating-diffusion node. The signal charges generated in the high-sensitivity photodiodes are transferred to the input of the comparator through an additional source follower, and the signal voltages converted by the source follower are compared with a reference voltage in the comparator. The output voltage of the comparator determines which photodiode is selected. Therefore, the proposed CIS composed of dual-sensitivity photodiodes extends the dynamic range according to the intensity of light. A $94{\times}150$ pixel array image sensor was designed using a conventional $0.18{\mu}m$ CMOS process and its performance was simulated.

Dynamic Analysis of an Optical Disk Drive for Wide Range Vibration Reduction by Using Dynamic Vibration Absorber (광디스크 드라이브의 광대역 진동저감을 위한 동흡진기 설계 및 동특성 해석)

  • 이동철;정진태;홍순교;김홍렬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.979-984
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    • 2003
  • A Dynamic vibration absorber(DVA) is developed to reduce the excessive vibration of an optical disk drive(ODD) originated from the deriving range of an wobble disk and unbalanced disk. We design the material properties and shapes of the DVA by simulating Frequency response function(FRF) such as target frequency, mass of the DVA, stiffness of damper, damping coefficient, shape and dimension, analyze dynamic characteristics and provide its design guide line for suppressing the vibration of an optical disk derive. To examine the performance of the DVA, the vibration of the feeding system with DVA and without DAA are measured by using a three-axis accelerometer, PCB derive and Pulse analyzer. The result show that the proposed DVA reduces the vibration of wide range in ODD.

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Spatial Resolution and Dynamic Range Enhancement Algorithm using Multiple Exposures (복수 노출을 이용한 공간 해상도와 다이내믹 레인지 향상 알고리즘)

  • Choi, Jong-Seong;Han, Young-Seok;Kang, Moon-Gi
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.6
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    • pp.117-124
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    • 2008
  • The approaches to overcome the limited spatial resolution and the limited dynamic range of image sensors have been studied independently. A high resolution image is reconstructed from multiple low resolution observations and a wide dynamic range image is reconstructed from differently exposed multiple low dynamic range in es based on signal processing approach. In practical situations, it is reasonable to address them in a unified context because the recorded image suffers from limitations of both spatial resolution and dynamic range. In this paper, the image acquisition process including limited spatial resolution and limited dynamic range is modelled. With the image acquisition model, the response function of the imaging system is estimated and the single image of which spatial resolution and dynamic range are simultaneously enhanced is obtained. Experimental results indicate that the proposed algorithm outperforms the conventional approaches that perform the high resolution and wide dynamic range reconstruction sequentially with respect to both objective and subjective criteria.

Design of the Transceiver for a Wide-Range FMCW Radar Altimeter Based on an Optical Delay Line (광 지연선 기반의 넓은 고도 범위를 갖는 고정밀 FMCW 전파고도계 송수신기 설계)

  • Choi, Jae-Hyun;Jang, Jong-Hun;Roh, Jin-Eep
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.11
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    • pp.1190-1196
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    • 2014
  • This paper presents the design of a Frequency Modulated Continuous Wave(FMCW) radar altimeter with wide altitude range and low measurement errors. Wide altitude range is achieved by employing the optic delay in the transmitting path to reduce the dynamic range of measuring altitude. Transmitting power and receiver gain are also controlled to have the dynamic range of the received power be reduced. In addition, low measurement errors are obtained by improving the sweep linearity using the Direct Digital Synthesizer(DDS) and minimizing the phase noise employing the reference clock(Ref_CLK) as the offset frequency of the Phase Locked Loop(PLL).

The development of IF amplifier having low noise and wide AGC range (저잡음 및 넓은 자동 이득 제어 영역을 갖는 IF 증폭기의 설계)

  • 이흥배;엄두찬;김용석;정연철
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.10
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    • pp.73-81
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    • 1994
  • It is AGC(Automatic Gain Control) amplifier to decide characteristics of IF(Intermediate Frequency) processing IC. When demodulated IF signal by PLL type demodulator, the amplitude of input singla should be maintained at a certain amplitude. The AGC amplifier is an important factor to achieve this condition. The AGC amplifier needs the wide dynamic range, the wide AGC range and better noise characteristics. We designed the AGC amplifier to satisfy these characteristics.

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Extension of the Dynamic Range in the CMOS Active Pixel Sensor Using a Stacked Photodiode and Feedback Structure

  • Jo, Sung-Hyun;Lee, Hee Ho;Bae, Myunghan;Lee, Minho;Kim, Ju-Yeong;Choi, Pyung;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.22 no.4
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    • pp.256-261
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    • 2013
  • This paper presents an extension of the dynamic range in a complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) using a stacked photodiode and feedback structure. The proposed APS is composed of two additional MOSFETs and stacked P+/N-well/P-sub photodiodes as compared with a conventional APS. Using the proposed technique, the sensor can improve the spectral response and dynamic range. The spectral response is improved using an additional stacked P+/N-well photodiode, and the dynamic range is increased using the feedback structure. Although the size of the pixel is slightly larger than that of a conventional three-transistor APS, control of the dynamic range is much easier than that of the conventional methods using the feedback structure. The simulation and measurement results for the proposed APS demonstrate a wide dynamic range feature. The maximum dynamic range of the proposed sensor is greater than 103 dB. The designed circuit is fabricated by the $0.35-{\mu}m$ 2-poly 4-metal standard CMOS process, and its characteristics are evaluated.

광대역 고감도 DLVA 개발

  • 이두훈;김상진;김재연;조현룡;이정문;김상기
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.4
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    • pp.39-52
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    • 2000
  • A design of 2 stage S-DLVA(successive detector log video amplifier) was studied to detect wide dynamic radar pulse ranging from -70 ㏈m to 0㏈m. A basic design idea was focused on the linear detection in logarithmic scale of wide dynamic range radar pulses from nosie-like weak power of -70 ㏈m to relatively high power 0 ㏈m. It is highly formidable, since it requires high speed detection less than 10 nsec over the operating frequency ranges from 6 to 18 ㎓. A limiter diode, a tunnel diode and an L17-C were used as a protecting device, a detector diode and a log video amplifier in companion as a single stage detector to give voltage output proportional to the input power of about 35 ㏈ dynamic range. A protype of 2-stage DLVA having one more single stage detector was fabricated with a 32 ㏈ low noise amplifier and a 3 ㏈ hybrid coupler to provide total 70 ㏈ dynamic range detection. The logging characteristics were measured to have log slope of 25m.V/㏈ against 70 ㏈ logging range from -55 ㏈m to +15 ㏈m, the log linearity of within +/- 1.5 ㏈, and tangential sensitivity was at -63 ㏈m. The pulse dynamics of rise time and recovery time were measured as 50 nsec and 1.2 $\mu$sec, respectively. The reason might be due to the parasitic capacitances of packaged limiter, tunnel diode, and L17-C.

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