Imaging systems having dual storage gate overflow capabilities
First Claim
1. An image sensor pixel, comprising:
- a photodiode that generates charge in response to incident light;
a first storage gate coupled to the photodiode, wherein the first storage gate comprises a first charge storage region;
a second storage gate coupled to the photodiode, wherein the second storage gate comprises a second charge storage region;
first, second, and third transistors;
a floating diffusion region coupled to the first storage gate through the first transistor; and
a capacitor coupled to the second charge storage region of the second storage gate through the second transistor, wherein the capacitor is coupled to the floating diffusion region through the third transistor, and wherein the third transistor has first and second terminals, the first transistor being coupled to the first terminal of the third transistor and the second transistor being coupled to the second terminal of third transistor.
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Accused Products
Abstract
An image sensor pixel may include a photodiode that generates first charge for a first frame and second charge for a second frame, first and second storage gates coupled to the photodiode, a floating diffusion coupled to the first storage gate through a first transistor, a second transistor coupled to the second storage gate, and a capacitor coupled to the floating diffusion through a third transistor. The image sensor pixel may output image signals associated with the first charge generated by the photodiode for the first image frame while the photodiode concurrently generates the second charge for the second image frame. The second storage gate may be used to store overflow charge. Overflow charge for the second frame may be stored at the second storage gate while image signals associated with the first image frame are read out from capacitor and the floating diffusion.
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Citations
19 Claims
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1. An image sensor pixel, comprising:
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a photodiode that generates charge in response to incident light; a first storage gate coupled to the photodiode, wherein the first storage gate comprises a first charge storage region; a second storage gate coupled to the photodiode, wherein the second storage gate comprises a second charge storage region; first, second, and third transistors; a floating diffusion region coupled to the first storage gate through the first transistor; and a capacitor coupled to the second charge storage region of the second storage gate through the second transistor, wherein the capacitor is coupled to the floating diffusion region through the third transistor, and wherein the third transistor has first and second terminals, the first transistor being coupled to the first terminal of the third transistor and the second transistor being coupled to the second terminal of third transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An image sensor pixel, comprising:
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a photodiode that generates charge in response to incident light; a first storage gate coupled to the photodiode; a second storage gate coupled to the photodiode; a first charge transfer transistor coupled to the photodiode through the first charge storage gate; a second charge transfer transistor coupled to the photodiode through the second charge storage gate; a photodiode reset transistor coupled to the photodiode; a floating diffusion region coupled to the first storage gate through the first charge transfer transistor, wherein the second storage gate is operable to store an overflow charge generated by the photodiode and wherein the first storage gate is operable to store a remaining charge that remains on the photodiode after the overflow charge has been transferred to the second storage gate; a gain selection transistor coupled to the floating diffusion region; and a capacitor coupled to the floating diffusion region through the gain selection transistor. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of operating an image sensor pixel having a photodiode, a floating diffusion region, a capacitor, a first storage gate coupled to the photodiode, a second storage gate coupled to the photodiode, a first transistor coupled between the first storage gate and a floating diffusion region, a second transistor coupled to the second storage gate, and a third transistor coupled between the capacitor and the floating diffusion region, the method comprising:
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with the photodiode, integrating a first charge for a given image frame; with the second storage gate, storing an overflow portion of the first charge for the given image frame; with the second and third transistors, transferring the overflow portion of the first charge to the capacitor and the floating diffusion region; with the first storage gate, storing a remaining portion of the first charge after the overflow portion of the first charge has been transferred to the capacitor and the floating diffusion region; with the photodiode, integrating a second charge for a subsequent image frame while an image signal associated with the transferred overflow portion of the first charge is concurrently read out from the image sensor pixel; and with the second storage gate, storing an overflow portion of the second charge for the subsequent image frame while the image signal associated with the transferred overflow portion of the first charge is concurrently read out from the image sensor pixel.
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Specification