Cmos image sensor with dual floating diffusions per pixel for flicker-free detection of light emitting diodes

Abstract

Apparatuses and methods for image sensors with pixels that reduce or eliminate flicker induced by high intensity illumination are disclosed. An example image sensor may include a photodiode, a transfer gate, an anti-blooming gate, and first and second source follower transistors. The photodiode may capture light and generate charge in response, and the photodiode may have a charge capacity. The transfer gate may selectively transfer charge to a first floating diffusion, and the anti-blooming gate may selectively transfer excess charge to a second floating diffusion when the generated charge is greater than the photodiode charge capacity. The first source-follower transistor may be directly coupled to the first floating diffusion by a gate, the first source-follower to selectively output a first signal to a first bitline in response to enablement of a first row selection transistor, and the second source-follower transistor may be capacitively-coupled to the second floating diffusion, the second source-follower to selectively output a second signal to a second bitline in response to enablement of a second row selection transistor.