Microsoft Corporation
Low power operation of differential image sensor pixels

Abstract:

An imaging system includes a sensor array of differential pixels. A controller operates a first differential pixel of the sensor array in a first, lower power mode. The controller supplies a first clock signal to selectively activate a first collection terminal of the first differential pixel for a first duration, and a second clock signal to selectively activate a second collection terminal of the first differential pixel for a second duration. In an analog domain, a first amount of charge accumulated at the first collection terminal over the first duration is readout and compared to a readout of a second amount of charge accumulated at the second collection terminal over the second duration. Responsive to the first amount of charge being different from the second amount of charge by more than a threshold, the first differential pixel of the sensor array is operated in a second, higher power mode.