Cmosis Bvba

Cmosis Nv

Gpixel Nv

Bram Wolfs

Guy Meynants

Jan Bogaerts

Xinyang Wang

Bart Ceulemans

A vertically stacked image sensor with HDR imaging functionality and a method of operating the same are disclosed. The image sensor comprises, a first substrate, a pixel array organized into a plurality of pixel subarrays, of which each pixel comprises a photoelectric element for integrating a photocharge during each one of a plurality of subframe exposures, a transfer gate and a buffered charge-voltage converter. A first charge accumulation element of the charge-voltage converter is operatively connectable to at least one second charge accumulation element through a gain switch. The image sensor comprises control circuitry configured to trigger a partial or a complete transfer of the and to time-interleave at least two rolling shutter control sequences. Separate readout blocks are provided on the second substrate for each pixel subarray, each comprising in a pipelined architecture an A/D conversion unit, a pixel memory logic and a pixel memory unit.

High dynamic range image sensor

An analog-to-digital conversion apparatuscomprises a plurality of analog-to-digital convertersand a ramp generator. Each of the analog-to-digital converterscomprises an analog signal input for receiving an analog signal level and a ramp signal input. A control stage is arranged to compare the ramp signal with the analog signal level and, based on the comparison, to enable a counter provided at the analog-to-digital converter or to latch a digital value received from a counter. The control stage comprises a comparator in the form of a first differential amplifier with a first branch connected to the input for receiving the ramp signal, a second branch connected to the analog signal input and an output, and a biasing current source for biasing the first differential amplifier. A feedback circuit controls the biasing current source. The feedback circuit comprises a second differential amplifier OPwith a first input connected to a nodeon the first branch and a second input connected to a reference voltage VB such that the node on the first branch is maintained at a substantially constant voltage.

Analog-to-digital conversion

An analog-to-digital converter for generating an output digital value equivalent to the difference between a first analog signal level (Vres) and a second analog signal level (Vsig) comprises at least one input for receiving the first analog signal level and the second analog signal level, an input for receiving a ramp signal and an input for receiving at least one clock signal. A set of N counters, where N&#x2267;2, are arranged to use N clock signals which are offset in phase from one another. A control stage is arranged to enable the N counters based on a comparison of the ramp signal with the first analog signal level (Vres) and the second analog signal level (Vsig). An output stage is arranged to output the digital value which is a function of values accumulated by the N counters during a period when they are enabled.

Analog-to-digital conversion in pixel arrays

A pixel structure comprises a photo-sensitive element for generating charge in response to incident light. A first transfer gate is connected between the photo-sensitive element and a first charge conversion element. A second transfer gate is connected between the photo-sensitive element and a second charge conversion element. An output stage outputs a first value related to charge at the first charge conversion element and outputs a second value related to charge at the second charge conversion element. A controller controls operation of the pixel structures and causes a pixel structure. The controller causes the pixel structure to: acquire charges on the photo-sensitive element during an exposure period; transfer a first portion of the charges acquired during the exposure period from the photo-sensitive element to the first charge conversion element via the first transfer gate; and transfer a second portion of the charges acquired during the exposure period from the photo-sensitive element to the second charge conversion element via the second transfer gate.

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Nieuwrode, Belgium

Bram Wolfs