Forza Silicon Corporation

Ali Mesgarani

Daniel A Van Blerkom

Steven Huang

Methods and systems for analog-to-digital conversion applicable to an image sensor, such as a CMOS image sensor, in which an ADC comprises built-in redundancy such that the ADC can start its conversion cycle before the ADC input settles to a desired resolution and the ADC can yet accurately convert the ADC input to a digital value with the desired resolution. In a CMOS image sensor, such an ADC configuration enables the pixel readout time to overlap with the ADC conversion time, reducing the total time needed to convert the pixel signal value to a digital value with the desired resolution.

Analog-to-digital converter with redundancy for image sensor readout

Presented herein are novel shared amplifier charge mode readout architectures for image sensors, for example, configured to process a pair of signals comprising photointegration and reset signals from a pixel. The invention encompasses a novel 2-channel configuration wherein a single amplifier can serve the two channels in alternating phases. In the first phase, a selected pair of signals from the first channel is read out to an ADC using the amplifier while the readout components of the second channel are reset. In the second phase, a selected pair of signals from the second channel is read out an ADC using the amplifier while the readout components of the first channel are reset. This alternating arrangement allows a single amplifier to be shared between two readout channels. Level shifting may be included in the signal pathway to modulate output swing and other signal parameters.

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Pasadena, CA, United States of America

Ali Mesgarani