Omnivision Technologies, Inc.

Tongtong Yu

Zhiyong Zhan

Xin Ru Wang

Zheng Yang

Liang Zuo

Kenny Geng

Wei Deng

An imaging system includes a pixel array configured to generate image charge voltage signals in response to incident light received from an external scene. An infrared illumination source is deactivated during the capture of a first image of the external scene and activated during the capture of a second image of the external scene. An array of sample and hold circuits is coupled to the pixel array. Each sample and hold circuit is coupled to a respective pixel of the pixel array and includes first and second capacitors to store first and second image charge voltage signals of the captured first and second images, respectively. A column voltage domain differential amplifier is coupled to the first and second capacitors to determine a difference between the first and second image charge voltage signals to identify an object in a foreground of the external scene.

Image sensor with in-pixel background subtraction and motion detection

A test voltage sample and hold circuitry is disclosed in a readout circuitry of an image sensor. This circuitry samples a voltage at demand value based on a ramp voltage shared by the ADC comparators of the readout circuitry. The value of the sampled voltage is controlled by a control circuitry which is able to predict and calculate at what time a ramp generator may carry the demand voltage value. The sampled voltage is held by a hold capacitor during readout of one row and is accessed during the next row by the control circuitry as test data to drive a device under test (DUT) which may be any portion of the image sensor to be tested. Measured data out of the DUT is compared with expected data. Based on the result of the comparison, a signal indicates the pass or fail of the self-test concludes a self-test of the DUT.

Image sensor with voltage buffer for self-test

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Fremont, CA, United States of America

Tongtong Yu