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US 9,313,428 B2Granted
Imaging sensors
AssigneeImec Vzw
InventorsJonathan Borremans, Koen De Munck
Life of this patent
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AssigneeImec Vzw
InventorsJonathan Borremans, Koen De Munck
Estimating the term…
Described herein is a pixel readout circuit which provides readout at two sensitivity levels depending on the amount of electrons generated by a pixel photodiode in the circuit. A floating diffusion capacitor operates to store charge up to a saturation value determined by its capacitance and an overflow capacitor is provided in an overflow region for storing charge above the saturation value of the floating diffusion capacitor. Readout at a high sensitivity level is provided when the floating diffusion capacitor is not saturated and readout at a lower sensitivity level is provided when there is saturation and subsequent overflow to the overflow region. Connection of the floating diffusion capacitor to the overflow capacitor shares the charge over the combined capacitance of the two capacitors and provides readout at a lower sensitivity without loss of charge.
A method for operating a light detection circuit comprising a first node, a second node, and a photodiode, the method comprising:
A light detection circuit comprising a photodiode, a first node, a second node, a first switch, a second switch, and a third switch, the light detection circuit being configured to perform functions comprising:
A light detection circuit comprising:
Dependencies are inferred from the claim text.