Abstract: An analog video bus architecture that utilizes the column parallel nature of CMOS imagers and more specifically Active Column Sensors, that eliminates the need for multi-port imagers, by increasing the useable bandwidth of single port imagers. An adaptation of this invention allows for either binning or interpolation of pixel information for increased or decreased resolution along the columns and more specifically for ACS imagers binning or interpolation along the rows. In this bus, the single video bus is replaced by multiple video buses and instead of selecting only one column for reading multiple columns are also pre-selected in-order to pre-charge the video bus. The video buses are then de-multiplexed back on to one port at the desired element rate. This architecture utilizes the column oriented video bus of CMOS imagers. It divides the large video bus capacitance by the number of video buses used. In addition, it allows multiple pixel time constants to precharge the video bus.

Abstract: A solid state imager includes an arrangement for converting analog pixel values to digital form on an arrayed per-column basis. An N-bit counter supplies an N-bit DAC to produce an analog ramp output providing a ramp signal with a level that varies corresponding to the contents of the counter. Latches or equivalent digital storage elements are each associated with a respective column. A counter bus connects the counter to latch inputs of said latches, and comparators associated the columns gate the latches when the analog ramp equals the pixel value for that column. The contents of the latch elements are transferred sequentially to a video output bus to produce the digital video signal. There can be additionally black-level readout latch elements, for storing a digital value that corresponds to the dark or black video level, and a subtraction element subtracts the black level value from the pixel value to reduce fixed pattern noise. An additional array of buffer latches can be employed.

Abstract: A bus system which includes two or more voltage-to-current transformers, a common bus, a terminal bus coupled to a voltage source, two or more first switches, and a selection circuit. Each of the voltage-to-current transformers converts a voltage signal to a current signal. The common bus carries the current signals from the voltage-to-current transformers to an output bus. Each of the first switches has a first position where an output from one of the voltage-to-current transformers is coupled to the common bus and a second position where the output is coupled to the terminal bus. The selection circuit is coupled to each of the first switches and controls movement of each of the first switches between the first and second positions.

Abstract: A new method of forming a photogate structure called a “Charge Snare Device” (CSD) uses only a single layer of polysilicon where prior art methods used two or more layers for constructing the gate nodes. Typical CCD structures utilize three layers of polysilicon and CID structures utilize two layers of polysilicon and neither of the prior art structures are suitable for standard sub micron processes. The new CSD device allows biasing of the photogate to the full potential that the process will allow for greater full well for a given pixel size and therefore an improved signal to noise ratio. Charge transfer between the collection site and the sense site isn't controlled as in all previous devices, rather the collection site is completely enclosed by the sense site, effectively snaring all collected photon generated charge as it diffuses and drifts to the sense site. The new photogate structure is suitable for passive pixels, Active Pixel Sensors (APS) or Active Column Sensors (ACS).

Abstract: An improved low voltage, small surface area, high signal-to-noise ratio photo gate includes a layer of photoreceptive semiconductor material having an impurity concentration selected to enhance the formation of hole electron pairs in response to photons impinging on a surface of the substrate, an electrode extending from the surface of the substrate into the substrate a substantial distance; an insulating layer disposed between the electrode and the substrate for electrically insulating the electrode from the substrate; so that upon the application of an electrical potential to the electrode, a potential well is formed in the substrate surrounding the electrode for accumulating charge generated when photons impinge on the surface of the substrate surrounding the electrode.

Abstract: A CMOS imager includes a photosensitive device such as a photosensitive device such as a photodiode or photogate having a sense node coupled to an FET located adjacent to the photosensitive region. Another FET, forming a differential input pair of an operational amplifier is located outside of the array of pixels. The operational amplifier is configured for unity gain and a row or column of input FETs is connected in parallel. A correlated double sampler is connected to the output of the operational amplifier for providing a fixed pattern noise free signal.