An anti-blooming charge accumulation pixel using an anti-blooming element coupled
to the pixel prevents blooming by ensuring that a voltage of a charge accumulation
device of the pixel is always returned to a clamping voltage following comparison
events. The anti-blooming element is used to return the voltage across a photodiode
to the supply voltage when both a low voltage comparison and a high voltage comparison
have occurred. A control block is used to determine an input signal to the anti-blooming
element based upon the result of a low voltage comparison and a high voltage comparison.
The input signal can be used to drive the anti-blooming element to a desired logic
level, thereby causing the voltage across the charge accumulation device to be
the clamping voltage. The use of the anti-blooming element eliminates blooming
to adjacent pixels, independent of an integration time of the pixel.
