Patent ID: 9426395
Filing Date: 2016-08-23
CPC Classification: H01L,H04N

Claim Text:
1. A method of calibrating a linear-logarithmic image sensor pixel, comprising: at least partially depleting a photodiode within the pixel; supplying a floating diffusion region within the pixel with a first subthreshold current by passing first photo-generated charge carriers from the at least partially depleted photodiode to the floating diffusion region; then reading a first voltage of the floating diffusion region containing the first photo-generated charges, as first calibration data; then, without resetting the floating diffusion region by removing the first photo-generated charges therefrom, supplying the floating diffusion region with a second subthreshold current by passing second photo-generated charge carriers from the at least partially depleted photodiode to the floating diffusion region; then reading a second voltage of the floating diffusion region containing the first and second photo-generated charge carriers therein, as second calibration data; and determining a knee-point voltage associated with a transition from a linear to logarithmic response of the pixel from the first and second calibration data.