Image sensors having high dynamic range functionalities

A method of operating an image sensor pixel that includes a photosensitive region, a charge storage region, first and second charge transfer transistors, a voltage supply, a reset transistor interposed between the voltage supply and the photosensitive region, and a floating diffusion region, the method comprising:

• with the photosensitive region, generating charge in response to light, wherein generating charge in response to light comprises generating a first set of charges during a first integration time period and generating a second set of charges during a second integration time period;
• with the voltage supply and the reset transistor, resetting the photosensitive region between the first and second integration time periods;
• with the first charge transfer transistor, transferring the first and second sets of charges from the photosensitive region to the charge storage region
• at the charge storage region, adding the first and second sets of charges to generate a summed charge;
• and
• with the second charge transfer transistor, transferring the summed charge from the charge storage region to the floating diffusion region.

A system, comprising:

• a central processing unit;
• memory;
• a lens;
• input-output circuitry;
• and
• a global shutter image pixel, wherein the global shutter image pixel comprises:
• a photodiode that generates image signals in response to light;
• a first transistor that sets a threshold voltage;
• a capacitor that is configured to receive a portion of the generated image signals that exceeds the threshold voltage and that stores the portion of the generated image signals;
• a storage region;
• a second transistor that is configured to transfer the portion of the generated image signals stored by the capacitor to the storage region;
• and
• a voltage supply that is coupled to the storage region through the second transistor, wherein the storage region is interposed between the first and second transistors.