CPC H04N 25/772 (2023.01) [H04N 25/42 (2023.01); H04N 25/50 (2023.01); H04N 25/709 (2023.01)] | 30 Claims |
1. An event driven pixel, comprising:
a photosensor configured to generate photocurrent in response to incident light received from an external scene;
a photocurrent-to-voltage converter coupled to the photosensor to convert the photocurrent to a first voltage; and
a difference circuit AC-coupled to the photocurrent-to-voltage converter,
wherein the difference circuit includes a source follower transistor and a switched-capacitor filter having an input coupled to the photocurrent-to-voltage converter and an output coupled to a gate of the source follower transistor,
wherein the switched-capacitor filter includes (a) a first capacitor coupled between the input and the output of the switched-capacitor filter, (b) a second capacitor having a first plate coupled to the output of the switched-capacitor filter, and (c) a reset transistor coupled between a reference voltage and the output of the switched-capacitor filter, and
wherein the difference circuit is configured to sample a reference light level based at least in part on the reference voltage and the first voltage at a first time, and to generate a difference signal based at least in part on a second voltage at the gate of the source follower transistor, wherein the second voltage is based at least in part on the reference light level and the first voltage at a second time, and wherein the difference signal is indicative of whether the event driven pixel has detected an event in the external scene.
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