US Patent 10397500 Wide dynamic range image sensor pixel cell

A pixel cell has a large and small photodiode, transfer transistors, a reset transistor, a dynamic range enhancement capacitor, a capacitor control transistor, a storage capacitor, a storage capacitor control transistor, an amplifier transistor in a source follower configuration and a rolling shutter row select transistor and a readout circuit block. The small and large photodiodes are exposed simultaneously, the large photodiode having a constant exposure while the small photodiode has a chopped exposure and charge transfer to a storage capacitor.