Patent ID: 8077238

Claim:
A method of operating a wide dynamic range pixel cell, the method comprising: resetting a photosensor to remove all charge from the photosensor by setting a reset signal to activate a reset transistor and pulsing a transfer signal to activate a transfer transistor, the photosensor comprising first and second charge accumulation regions having respective first and second pinned voltages; exposing the photosensor to light during an integration period, the photosensor capable of converting the light into charges; draining said charges from said first accumulation region into said second accumulation region; setting an anti-blooming transistor to drain excess charge from the second charge accumulation region into a drain region; and performing a readout of the charges generated by the photosensor during the integration period, wherein a set point of the anti-blooming transistor is set by the respective first and second pinned voltages of the first and second charge accumulation regions.