Abstract: Disclosed herein is a Complementary Metal-Oxide-Silicon (CMOS) image sensor. The image sensor includes a two-dimensional pixel array composed of unit pixels, each unit pixel having a photo diode and transistors, a row decoder located at an end of the pixel array to assign row addresses, and a column decoder located at another end of the pixel array, which is erpendicular to the row decoder, to assign column addresses to corresponding pixels in rows selected by the row decoder. The row decoder allows the integration time points of the unit pixels, which are included in the pixel array, to be identical. Accordingly, the distortion of images can be prevented.

Abstract: A solid-state imaging device includes: a pixel array unit including unit pixels arranged in a matrix, each of the unit pixels having a photoelectric conversion element that converts a light signal to a signal charge, an amplifying transistor that amplifies and outputs the signal charge as a signal voltage, and a capacitive element whose one end is connected to a control electrode of the amplifying transistor; a driving means for selectively supplying a predetermined voltage to the other end of the capacitive element; and a signal processing circuit that performs a predetermined signal processing with respect to a signal output from each pixel of the pixel array unit.

Abstract: An image capturing element having an electric shutter function of controlling exposure time for each frame includes: a photoelectric converter that has a plurality of photoelectric conversion elements arranged in a matrix each of which converts light into charge and stores the converted charge; a first reading unit that reads charge exposed for a predetermined exposure time from each pixel formed by the photoelectric conversion element in the entire exposure region of the photoelectric converter by a destructive readout method; and a second reading unit that reads charge from each pixel formed by the photoelectric conversion element in a specific region, which is a portion of the entire exposure region of the photoelectric converter, plural times by a non-destructive readout method in a period in which the first reading unit reads the charge from the entire exposure region.

Abstract: An image sensor includes a pixel having a protection circuit connected to a charge multiplying photoconversion layer. The protection circuit prevents the pixel circuit from breaking down when the voltage in the pixel circuit reaches the operating voltage applied to the charge multiplying photoconversion layer in response to the image sensor being exposed to a strong light. The protection circuit causes additional voltage entering the pixel circuit from the charge multiplying photoconversion layer over a predetermined threshold voltage level to be dissipated from the storage node and any downstream components.

Abstract: A CMOS color image sensor, which is a solid-state image pickup device, includes a plurality of pixels arranged in a matrix having a plurality of rows and a plurality of columns, each of the plurality of pixels converting the incident light intensity into an electrical signal; a pixel array including the plurality of pixels; row-selection lines; and column-reading lines. Two column-reading lines are provided for each column of the pixel array. Pixels in even rows of each column are connected to one column-reading line and pixels in odd rows of each column are connected to the other column-reading line.

Abstract: A wafer-scale linear image sensor chip (WLISC) is proposed with gapless pixel line and signal readout circuit segments. The WLISC converts pixel line image (PLI) of length LPL into line image signal (LIS). The WLISC includes a linear array of sensor segments. Each sensor segment includes a gapless local pixel line segment (LPLSj) of sensing elements. The LPLSj converts portion of the PLI into a raw image segment signal set (RISSj). The LPLSj set forms a gapless global pixel line (GPL) corresponding to PLI. The sensor segment also includes readout circuit segment (RCSj) coupled to LPLSj for processing RISSj into a readout image segment signal set (ROSSj). The RCSj has a set of contact pads (CTPj) for off-chip interconnection. Upon off-chip interconnection of the CTPj set thus composing the ROSSj set into LIS, the WLISC functions as a key part of a linear image sensor system of image length LPL.

Abstract: An image sensor circuit includes a pixel array, a plurality of column analog-to-digital conversion (ADC) circuits, and at least two memory blocks. Each column ADC circuit is connected to receive analog pixel signals provided from corresponding pixel circuits of the pixel array, and is configured to convert the received analog pixel signals into digital pixel signals. Each memory block is connected to receive digital pixel signals provided from corresponding column ADC circuits of the plurality of column ADC circuits. At least two of the at least two memory blocks are connected to receive digital pixel signals that are provided from corresponding column ADC circuits that are located to a same side of the pixel array. Each memory block of the at least two memory blocks includes a plurality of memory cells, one or more sense amplifiers connected to the memory cells by a readout bus, and a memory controller.

Abstract: Methods, devices, and systems for offset compensation in an amplifier are disclosed, wherein the amplifier inputs may be exposed to large loads from an array of pixel columns coupled in parallel. During a sampling phase, an amplifier offset may be sampled by selectively coupling a first amplifier output to a first amplifier input and a second amplifier output to a second amplifier input. During a portion of the sampling phase, the first amplifier output may be buffered to a first storage element. During a different portion of the sampling phase, the second amplifier output may be buffered to a second storage element. To sense the pixel columns during an amplification phase, the first storage element and the second storage element are coupled to the first and second amplifier inputs, respectively, with the result that the amplifier offset is canceled from the amplifier output.

Abstract: An apparatus includes a plurality of pixels including a photoelectric conversion unit and a pixel amplification unit for amplifying a signal transmitted from the photoelectric conversion unit and outputting an amplified signal, a sequential averaging unit configured to sequentially average signals read a plurality of times via the pixel amplification unit, and a memory configured to store a signal obtained by sequential averaging.

Abstract: A solid state imaging device including: a pixel portion having a plurality of pixels arrayed two-dimensionally and including an effective pixel portion and a dummy pixel portion; a timing generator for generating address information for reading signals of pixels of the pixel portion and timing signals for reading; a column decoder; a column selection circuit for generating transfer signals and reset signals used for control for reading signals of pixels in the column portions of the pixel portion by the plurality of line selection signals output from the column decoder based on the timing signals and selecting column portions of pixels in an effective portion and a dummy portion of the pixel portion; and a transfer circuit for reading signals of corresponding pixels based on the transfer signals and reset signals output from the column selection circuit, then transferring signals of read pixels by the row signal lines.

Abstract: In an image sensor, the current through the in-pixel readout transistor is sensed by a circuit that is external to the pixel, and according to the measured current value a feedback current is supplied to charge the read-line parasitic capacitance. The feedback current is supplied by a circuit that also is external to the pixel area. The amplifier structure is reconfigurable so that it can be used both to read out and to reset the pixel.

Abstract: An control unit of the amplification type solid-state image pickup device, during a first period T2, controls the gate voltage of the transfer transistor to a first gate voltage V1 to make electrons as signal charge transferred from the phototransistor to the charge detection part. Also, the control unit, in a second period T3 subsequent to the first period T2, sets the gate of the transfer transistor to a high impedance and moreover, in a period TPU within the second period T3, controls the gate voltage of the transfer transistor to a second gate voltage V2 which allows power of transferring the signal charge to the charge detection part to be enhanced than the first gate voltage V1.

Abstract: There is provided an image sensing apparatus.

Abstract: By providing dummy pixels separately from effective pixels, the total number of pixel rows is equalized with the number of horizontal sync signals included in one frame interval (which is called an “HD number”). A period during which a reset signal for an electronic shuttering operation is being supplied to an arbitrary pixel row overlaps with a period during which another pixel row is selected to perform a readout operation thereon. Thus, it is possible to suppress a variation in reset potential among effective pixels.

Abstract: The present invention relates to a photo-detecting apparatus having a structure for enabling photodetection with high sensitivity and wide dynamic range. When light is incident on a pixel section of an active pixel-type within a photo-detecting section, a voltage value corresponding to the amount of an electric charge generated at a photodiode included in the pixel section is outputted from the pixel section by way of a selecting transistor. A first pixel data readout section outputs the output from the pixel section as a first voltage value. On the other hand, the electric charge generated at the photodiode including the pixel section is outputted from the pixel section by way of a discharging transistor. The electric charge flown in a second pixel data readout section via a switch is accumulated in a capacitive element, and a voltage value corresponding to the amount of the accumulated electric charge is outputted from the second pixel data readout section as a second voltage value.

Abstract: An object of the present invention is to provide a solid-state imaging apparatus capable of providing a high S/N ratio in a plurality of operation modes, and a method for driving the same. Provided is a solid-state imaging apparatus including: a plurality of pixels (1), each of the pixels including a photoelectric conversion unit for generating a charge by photoelectric conversion and accumulating the charge; and an amplifier 2 connected to a plurality of the pixels, to amplify the charge generated by the pixels, wherein the amplifier 2 includes an offset voltage setting unit (SW1) for setting at least two offset voltages.

Abstract: Signals from an object in a field of view are detected by an array of directional sensors and “re-converged” to create a three-dimensional image as the object changes contrast or moves relative to the sensors. Each sensor is oriented along an axis toward the field of view. Sensor signals are converted to logarithms thereof and transients are detected and compared to background signals. Resulting signals are connected in overlapping groups to coincidence detectors in a matrix. Each point in the field of view where two or more sensor axes intersect is represented by a coincidence detector, which is connected to the corresponding group of sensors. If a threshold number of sensors in the group detects a transient, the corresponding point in the image is deemed to be “contrasty” and can be made visible or otherwise perceivable by a human or can be further processed by a computer or other circuit.

Abstract: A solid-state imaging device includes photo-sensitive cells for converting incident light to signal charges, and a transfer path for transferring, in response to a drive signal fed through a transfer electrode, the signal charges read out from the photo-sensitive cells. The solid-state imaging device outputs electrical signals corresponding to the signal charges thus transferred. The transfer electrode is divided into a first transfer electrode for transferring the signal charges and a second transfer electrode for reading out the signal charges from the photo-sensitive cells.

Abstract: Provided is a solid-state imaging apparatus that is capable of preventing a harmful influence due to noise generated in a control line. The solid-state imaging apparatus includes: a plurality of pixels each including a photoelectric conversion unit for photoelectric converting to generate a signal; control lines for supplying control signals for driving the pixels; driving buffers for driving the control lines; and switching units for switching between a first path for supplying power source voltages from power source circuits to power source terminals of the driving buffers and a second path for supplying power source voltages from capacitors to the power source terminals of the driving buffers.

Abstract: A pixel circuit having an improved dynamic range is disclosed. When incoming light detected by the photodiode is strong, the accumulated (integrated) charge on a signal capacitor becomes large. To compensate, the excess signal component becomes compressed and the pixel circuit begins operating in logarithmic rather than linear mode. In this way, the circuit can achieve a higher dynamic range more closely resembling the image sensing properties of the human eye.

Abstract: Pixels are two-dimensionally arranged into rows and columns in an image sensing region of a solid-state image sensing device, and divided into a plurality of vertical blocks. A vertical signal line is connected to each pixel column. A voltage read out from a pixel is A/D-converted and held in a holding circuit. A vertical block selection circuit outputs a vertical block selection signal in response to a horizontal sync pulse. An intra-block line selection circuit selects one pixel row in one block or simultaneously selects a plurality of pixel rows in one block, in accordance with the selection signal and a signal for setting the number of lines to be selected. A pulse selector circuit supplies a pixel driving pulse signal to a pixel row selected by the intra-block line selection circuit.

Abstract: Systems and methods for providing one or more reference currents with respective negative temperature coefficients are provided. A first voltage is divided to provide a divided voltage, which is compared to a reference voltage (e.g., a bandgap reference voltage) to provide a control voltage. The first voltage and the one or more reference currents are based on the control voltage.

Abstract: Photosensitive cells each includes a photodiode (1), a transfer gate (2), a floating diffusion layer portion (3), an amplifying transistor (4), and a reset transistor (5). Drains of the amplifying transistors (4) of the photosensitive cells are connected to a power supply line (10), and a pulsed power supply voltage (VddC) is applied to the power supply line (10). Here, a low-level potential (VddC_L) of the power supply voltage has a predetermined potential higher than zero potential. Specifically, by making the low-level potential (VddC_L) higher than channel potentials obtained when a low level is applied to the reset transistors (5), or channel potentials obtained when a low level is applied to the transfer gates (2), or channel potentials of the photodiodes (1), a reproduced image with low noise is read.

Abstract: A solid-state imaging device is capable of simplifying the pixel structure to reduce the pixel size and capable of suppressing the variation in the characteristics between the pixels when a plurality of output systems is provided. A unit cell (30) includes two pixels (31) and (32). Upper and lower photoelectric converters (33) and (34), transfer transistors (35) and (36) connected to the upper and lower photoelectric converters, respectively, a reset transistor (37), and an amplifying transistor (38) form the two pixels (31) and (32). A full-face signal line 39 is connected to the respective drains of the reset transistor (37) and the amplifying transistor (38). Controlling the full-face signal line (39), along with transfer signal lines (42) and (43) and a reset signal line (41), to read out signals realizes the simplification of the wiring in the pixel, the reduction of the pixel size, and so on.

Abstract: Solid state CMOS active pixel sensor devices having unit pixels that are structured to provide improved uniformity of pixel-to-pixel sensitivity across a pixel array without the need for an additional light shielding layer. For example, unit pixels with symmetrical layout patterns are formed whereby one or more lower-level BEOL metallization layers are designed operate as light shielding layers which are symmetrically patterned and arranged to balance the amount of incident light reaching the photosensitive regions.

Abstract: A pixel for an imaging device is described. The pixel includes a photosensitive device provided within a substrate for providing photo-generated charges, a circuit associated with the photosensitive device for providing at least one pixel output signal representative of the photo-generated charges, the circuit includes at least one operative device that is responsive to a first control signal during operation of the associated circuit and a pump circuit. The pump circuit may include substrate pumps, charge pumps and/or voltage pumps. The pixel may also be embedded in an imaging system.

Abstract: A plurality of pixel groups X(n) each comprising a plurality of pixels are set, and switched capacitor amplification parts are provided in correspondence to the pixel groups, respectively. Each of the switched capacitor amplification parts has a charge detection node to which output terminals of the transfer transistors of a corresponding pixel group X(n) are connected in common, an amplification part, a reset transistor, a first capacitance element, and a select transistor. A load part common to the switched capacitor amplification parts is provided. The load part is combined with the amplification parts of the switched capacitor amplification parts to constitute inverting amplifiers, respectively. By means of the above constitution, it is capable of obtaining a noise-reduced, high-quality image and which allows transistor count per pixel to be cut, thus allowing the pixel size to be reduced.

Abstract: An image sensor includes a plurality of pixels, at least two pixels each having a photodetector; a charge-to-voltage conversion region; an input to an amplifier; and a switch for selectively connecting the charge-to-voltage conversion regions.

Abstract: A solid state image sensor includes a pixel array, as well as charge-to-voltage converters, reset gates, and amplifiers each shared by a plurality of pixels in the array. The voltage level of the reset gate power supply is set higher than the voltage level of the amplifier power supply. Additionally, charge overflowing from photodetectors in the pixels may be discarded into the charge-to-voltage converters. The image sensor may also include a row scanner configured such that, while scanning a row in the pixel array to read out signals therefrom, the row scanner resets the charge in the photodetectors of the pixels sharing a charge-to-voltage converter with pixels on the readout row. The charge reset is conducted simultaneously with or prior to reading out the signals from the pixels on the readout row.

Abstract: Solid-state imaging device having a plurality of vertical signal lines, includes for each vertical signal line, an effective pixel and a dummy pixel, a switch transistor provided on a path connecting the dummy pixel and the vertical signal line, and a read-out unit. The switch transistor is OFF while a first signal is outputted from the effective pixel and ON while a second signal is outputted from the dummy pixel. The read-out unit (i) reads out a level of the first signal while the switch transistor is OFF, and (ii) reads out a difference between the level of the first signal and a level of the second signal when the switch transistor is turned from OFF to ON.

Abstract: A solid-state imaging device includes a substrate, a sensor cell array disposed on the substrate, the sensor cell array having a plurality of sensor cells arranged in a matrix, a plurality of signal lines for transferring an image signal output from each of the sensor cells, a plurality of amplifiers connected to at least one of the signal lines, each of the amplifiers including a first capacitance having a first end connected to one of the signal lines, an inversion amplifier having an input end connected to a second end of the first capacitance, a second capacitance connected between the input end and an output end of the inversion amplifier, a switch connected between the input and output ends of the inversion amplifier to reset the second capacitance and a third capacitance having a first end connected to a control line and a second end connected to the input end of the inversion amplifier, and a control voltage supply circuit for supplying one of first and second voltages to the control line.

Abstract: The invention relates to an image sensor for cameras which includes a plurality of pixels arranged in lines and columns. The pixels each include a light-sensitive detector element to generate electrical charge from incident light, a transfer gate, a readout node which is charge-coupled to the detector element via the transfer gate, a converter circuit to generate a measurement signal which is proportional to a charge present in the readout node, and a reset device to reset a charge present in the readout node to a reference value. The image sensor furthermore includes a control device for the control of the transfer gate and of the of the reset device of the respective pixel. The control device is configured such that the charge generated during a single exposure procedure in the respective detector element is transferred from the detector element to the readout node in a plurality of portions. The invention furthermore relates to a method for the reading out of an image sensor.

Abstract: In a solid-state image-sensing device, after completion of image sensing by individual pixels, in each pixel, a signal ?VRB fed to a capacitor C1 connected to the gate of a first MOS transistor T1 is turned to a high level to make it easy for a negative electric charge to flow into the MOS transistor T1. This permits quick recombination of the positive electric charges accumulated at the drain and gate of the MOS transistor T1, at the gate of a MOS transistor T2, at the anode of a photodiode, and in a capacitor C2, and thereby makes quick resetting possible.

Abstract: In an image capture mode, a noise reading operation and image signal reading operation are used. In a photometric operation mode, the image signal reading operation is used.

Abstract: An image sensing device comprises: a pixel array in which a plurality of pixels are arrayed; and a plurality of column amplification units that amplify a plurality of signals that are output in parallel from the pixel array, wherein each of the column amplification units includes: a differential amplifier including an amplification unit and a constant current circuit, the amplification unit amplifying a signal that is output from the pixels and outputting the signal to an output node, the constant current circuit being arranged between the amplification unit and a ground terminal and supplying a current to the amplification unit; and a clip unit that clips a voltage of the output node when the differential amplifier amplifies the signal and thereby clipping a voltage of a connection node connecting the amplification unit to the constant current circuit in the differential amplifier.

Abstract: An image sensor includes a matrix of active pixels (PXA). A pair of sampling capacitors (C1) and (C2) per matrix column processes the information delivered by the active pixel matrix. Each matrix column further includes a differential amplifier configured in follower mode connected between the pixels of the column and the pair of sampling capacitors via a pair of switches (I1) and (I2).

Abstract: In an image sensing apparatus having a plurality of unit cells, each including a plurality of photoelectric conversion elements and a common circuit shared by the plurality of photoelectric conversion elements, arranged in either one or two dimensions, the plurality of photoelectric conversion elements are arranged at a predetermined interval.

Abstract: A reset transistor includes a floating diffusion region for detecting a charge, a junction region for draining the charge, a gate for controlling a transfer of the charge from the floating diffusion region to the junction region upon receipt of a reset signal, and a potential well incorporated underneath the gate.

Abstract: An image sensor circuit includes a pixel array, a plurality of column analog-to-digital conversion (ADC) circuits, and at least two memory blocks. Each column ADC circuit is connected to receive analog pixel signals provided from corresponding pixel circuits of the pixel array, and is configured to convert the received analog pixel signals into digital pixel signals. Each memory block is connected to receive digital pixel signals provided from corresponding column ADC circuits of the plurality of column ADC circuits. At least two of the at least two memory blocks are connected to receive digital pixel signals that are provided from corresponding column ADC circuits that are located to a same side of the pixel array. Each memory block of the at least two memory blocks includes a plurality of memory cells, one or more sense amplifiers connected to the memory cells by a readout bus, and a memory controller.

Abstract: An image sensor has a plurality of pixels, each pixel having a photodiode (12), a voltage amplifier (16) having gain magnitude greater than 1 and a sampling capacitor (18) charged by the voltage amplifier. In this arrangement, each pixel provides gain through voltage amplification. This enables the sampling capacitor to be kept to a low size, so that the pixel circuitry occupies the smallest possible space, thereby enabling large aperture pixels to be formed. A source-follower buffer transistor (49) is provided at the input to the voltage amplifier. This overcomes the effect of charge sharing resulting from the parasitic capacitances of the output transistor of the voltage amplifier.

Abstract: Signals from an imager pixel photodetector are received by an amplifier having capacitive feedback, such as a capacitive transimpedance amplifier (CTIA). The amplifier can be operated at a low or no power level during an integration period of a photodetector to reduce power dissipation. The amplifier can be distributed, with an amplifier element within each pixel of an array and with amplifier output circuitry outside the pixel array. The amplifier can be a single ended cascode amplifier, a folded cascode amplifier, a differential input telescopic cascode amplifier, or other configuration. The amplifier can be used in pixel configurations where the amplifier is directly connected to the photodetector, or in configurations which use a transfer transistor to couple signal charges to a floating diffusion node with the amplifier being coupled to the floating diffusion node.

Abstract: An image sensing apparatus comprises a transfer block including a first transfer unit and a second transfer unit, wherein the first transfer unit includes a first impedance converter which transfers a first signal to the output unit, and the first transfer unit transfers, as a third signal, a difference signal between a first offset of the first impedance converter and a signal obtained by superimposing the first offset on the first signal, the second transfer unit includes a second impedance converter which transfers a second signal to the output unit, and the second transfer unit transfers, as a fourth signal, a difference signal between a second offset of the second impedance converter and a signal obtained by superimposing the second offset on the second signal, and the output unit calculates a difference between the third signal and the fourth signal, generating and outputting an image signal.

Abstract: The present invention aims at providing a photodetector which can detect the incident light intensity with a high speed while having a wide dynamic range for incident light intensity detection. Each photodiode PDm,n generates electric charges Q by an amount corresponding to the intensity of light incident thereon. An electric charge amount level determining circuit 10m,n is provided so as to correspond to the photodiode PDm,n, determines the level of the amount of electric charges Q generated by the photodiode PDm,n, and outputs a level signal Level indicative of the result of level determination. The capacitance value of the integral capacitance part 21 in the integrating circuit 20m is set by the respective level signals Level sequentially fed from N electric charge amount level determining circuits 10m,1 to 10m,N.

Abstract: A solid-state imaging device includes: plural pixel cells, arranged in a matrix, each of which includes a photodiode which photoelectrically converts incident light, a transferring transistor which transfers a charge generated by the photodiode, a floating diffusion which accumulates the transferred charge, a reset transistor which resets a potential of said floating diffusion, and an amplifying transistor which converts the charge accumulated in the floating lo diffusion into a voltage; column signal lines each connected to associated ones of plurality of amplifying transistors including the amplifying transistor corresponding to a corresponding one of columns having the associated plurality of pixel cells; and a voltage control circuit which increases a voltage of the column signal line to a predetermined voltage between the reset of the potential by the reset transistor and the transfer of the charge by the transferring transistor.

Abstract: The present invention includes operational amplifier for an active pixel sensor that detects optical energy and generates an analog output that is proportional to the optical energy. The active pixel sensor operates in a number of different modes including: signal integration mode, the reset integration mode, column reset mode, and column signal readout mode. Each mode causes the operational amplifier to see a different output load. Accordingly, the operational amplifier includes a variable feedback circuit to provide compensation that provides sufficient amplifier stability for each operating mode of the active pixel sensor. For instance, the operational amplifier includes a bank of feedback capacitors, one or more of which are selected based on the operating mode to provide sufficient phase margin for stability, but also considering gain and bandwidth requirements of the operating mode.

Abstract: A solid-state image sensor comprises unit pixels each having a photoelectric conversion element for converting incident light into electric signal charge and then storing the signal charge obtained through such photoelectric conversion, an amplifying element for converting into an electric signal the signal charge stored in the photoelectric conversion element, and a select switch for selectively outputting the pixel signal from the amplifying element to a signal line. The image sensor further comprises a reset circuit in each of the unit pixels for resetting the photoelectric conversion element every time a pixel signal is outputted from the relevant unit pixel.

Abstract: Provided is a photoelectric conversion device, including: a plurality of photoelectric conversion blocks each including a photoelectric conversion element, photoelectric conversion element resetting means for supplying an initialization potential to the photoelectric conversion element to reset the photoelectric conversion element, and transfer means for transferring a voltage of the photoelectric conversion element, in which the photoelectric conversion element resetting means resets the photoelectric conversion element every time the voltage of the photoelectric conversion element is transferred and for a standby period, during a reading period. Therefore, it is possible to perform accurate image reading by reducing the influence of a foreign matter adhered to a light receiving surface of a photoelectric conversion device.

Abstract: In one aspect of the present application, provided is a charge gain imaging system and a method of operating the charge gain imaging system. The method includes collecting a pixel charge. The collected pixel charge being stored by a pixel capacitance (Cp). Thereafter the pixel having the stored pixel charge is selected via a pixel select switch, and the pixel voltage is transferred and stored by data line capacitance (Cd) of a data line of the imager. An amplifier select switch is activated connecting the data line to a charge amplifier, and a charge gain defined by a relationship Cd/Cp, is sensed by a charge amplifier.

Abstract: A method and apparatus are provided for operation of an image sensor during signal readout. During a reset operation the gate of a reset transistor coupled to the storage node receives a voltage greater than a threshold voltage to produce a reset of the storage node. During a period where photogenerated charges stored at the storage node are read out the gate of the reset transistor receives a voltage VRST—LOW greater than ground, but less than a maximum voltage which can be stored at the storage node.

Abstract: A system and method are disclosed to enlarge the sub-threshold current coefficient “?” of a reset transistor connected to a photodiode in an L-L (Linear Logarithmic) pixel sensor without modifying any semiconductor process parameters. In one embodiment, a coupling capacitor is introduced between the gate and source terminals of the reset transistor. The gate node of the reset transistor is kept floating and the change in its source voltage Vs is coupled to its gate voltage Vg by a certain rate with the help of the coupling capacitor. Thus, an effective change in (Vg-Vs) is made small, which is equivalent to enlarging the sub-threshold coefficient “?” In this manner, the signal gain in the logarithmic region of operation of the pixel sensor can be controlled by changing the coupling capacitance between the source and gate terminals of the reset transistor connected to the photodiode. The signal conversion gain in the logarithmic region is increased, but the gain in the linear region is unchanged.