Clamped capacitor readout noise rejection circuit for imagers
AssigneeMicron Technology, Inc.
InventorRoger Panicacci
Life of this patent
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Abstract
An imaging device with readout chain circuitry that uses cascaded gain stages to amplify pixel and reset signals from odd and even columns of pixels. The readout chain shares amplifiers between odd and even channels. The last stage of the chain includes noise suppression circuitry designed to suppress kTC and amplifier thermal noise during the readout process.
Claims33
A readout chain for an imaging device, said readout chain comprising:
- first and second stages coupled to receive pixel and reset signals from a column of pixels, said first and second stages being cascaded;
- and
- a third stage coupled to the output of the second stage, said third stage comprising noise suppression circuitry for substantially suppressing noise associated with said first and second stages.
An imaging device comprising:
- an array of pixels organized in to even and odd columns;
- and
- a plurality of readout chains, each readout chain comprising:
- sample and hold circuitry coupled to receive pixel and reset signals from a column of pixels;
- first and second stages coupled to receive sample and held pixel and reset signals from said sample and hold circuitry, said first and second stages being cascaded;
- and
- a third stage coupled to the output of the second stage, said third stage comprising noise suppression circuitry for substantially suppressing noise associated with said first and second stages.
A processor system comprising:
- a processor;
- and
- an imaging device coupled to said processor, said imaging device comprising an array of pixels organized in to even and odd columns, and a plurality of readout chains, each readout chain comprising:
- sample and hold circuitry coupled to receive pixel and reset signals from a column of pixels;
- first and second stages coupled to receive sample and held pixel and reset signals from said sample and hold circuitry, said first and second stages being cascaded;
- and
- a third stage coupled to the output of the second stage, said third stage comprising noise suppression circuitry for substantially suppressing noise associated with said first and second stages.
An imaging device comprising:
- an array of pixels organized in to even and odd columns;
- and
- a plurality of readout chains connected to the columns, said readout chains being operated such that at least one readout chain substantially suppresses noise associated with said readout chains while at least another readout chain is reading signals from the pixels.
An imaging device comprising:
- an array of pixels organized in to even and odd columns;
- and
- a plurality of readout chains connected to the columns, said readout chains sharing amplifiers to substantially increase speed and being operated such that at least one readout chain is clamped to a known voltage while at least another readout chain is reading signals from the pixels using the shared amplifiers.
A method of fabricating a readout chain for an imaging device, said method comprising the acts of:
- forming first and second stages coupled to receive pixel and reset signals from a column of pixels, the first and second stages being cascaded;
- and
- forming a third stage coupled to the output of the second stage, the third stage comprising noise suppression circuitry for substantially suppressing noise associated with the first and second stages.
A method operating an imaging device, said method comprising the acts of:
- resetting first and second gain stages of a first readout channel;
- inputting pixel and reset signals from a column of pixels into the first gain stage;
- storing noise associated with the operation of the first and second stages in a third stage;
- amplifying the input signals with a gain of the first gain stage;
- amplifying the amplified signals with a gain of the second gain stage;
- and
- processing the amplified signals while subtracting out the stored noise in the third stage.
Dependencies are inferred from the claim text.