US6128039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Column amplifier for high fixed pattern noise reduction
Assignee: Omnivision Technologies Inc
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Filing: 1999-01-11
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Granted: 2000-10-03
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Expires: 2019-01-11
Abstract
Abstract A column amplifier for high fixed pattern noise reduction. The column amplifier includes a switching capacitor amplifier, a sample and hold stage, and an output buffer. The switching capacitor amplifier receives signals from a bit line that is coupled to a column of active pixel sensors. The switching capacitor amplifier is capacitively coupled to the bit line from a column of active pixel sensors and is able to cancel the common mode offset in the bit line. The common mode can also be adjusted in the switching capacitor amplifier, such that the last stage of the column amplifier (e.g., the buffer stage) is not limited by the common mode level of the active pixel sensors. The switching capacitor amplifier includes an input capacitor and a feedback capacitor. The gain of the switching capacitor amplifier amplifies the pixel signals so that the fixed pattern noise introduced by stages after the switching capacitor amplifier will comprise a lower proportion of the total signal.
Inventors
- 👤 Datong Chen
- 👤 Xinping He
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:57
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/28; G11C19/282; G11C19/285; G11C27/00; G11C27/02; G11C27/024; G11C27/026; H; H03; H03F; H03F3/00; H03F3/005; H04; H04N; H04N25/00; H04N25/60; H04N25/616; H04N25/67; H04N25/671; H04N25/677; H04N25/70; H04N25/76; H04N25/78
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
161 words
A column amplifier for use in an image sensor, said image sensor including a plurality of pixels organized into rows and columns, at least one of said columns having the signals from its pixels being carried by a bit line for further signal processing, said column amplifier comprising: (a) a signal amplifier for amplifying signals from the bit line, the signal amplifier including at least one input and at least one output; (b) an input capacitor capacitively coupling an input of the signal amplifier to the bit line; (c) a feedback capacitor coupled directly in a feedback path between an input of the signal amplifier and an output of the signal amplifier; and (d) a switch between said input of the signal amplifier and said output of the signal amplifier, said switch being in parallel with said feedback capacitor to selectively bypass said feedback capacitor; wherein no other electrically active element other than said feedback capacitor is in said feedback path.
Claim 2
Dependent Claim
161 words
A column amplifier for use in an image sensor, said image sensor including a plurality of pixels organized into rows and columns, at least one of said columns having the signals from its pixels being carried by a bit line for further signal processing, said column amplifier comprising: (a) a signal amplifier for amplifying signals from the bit line, the signal amplifier including at least one input and at least one output; (b) an input capacitor capacitively coupling an input of the signal amplifier to the bit line; (c) a feedback capacitor coupled directly in a feedback path between an input of the signal amplifier and an output of the signal amplifier; and (d) a switch between said input of the signal amplifier and said output of the signal amplifier, said switch being in parallel with said feedback capacitor to selectively bypass said feedback capacitor; wherein no other electrically active element other than said feedback capacitor is in said feedback path.
Claim 3
Dependent Claim
28 words
The column amplifier of claim 1, further comprising a sample and hold stage coupled to an output of the signal amplifier and having an input and an output.
Claim 4
Dependent Claim
21 words
The column amplifier of claim 2, further comprising a buffer stage coupled to the output of the sample and hold stage.
Claim 5
Dependent Claim
36 words
The column amplifier of claim 3, wherein the sample and hold stage includes at least two sampling capacitors and the buffer stage includes at least two buffers, the buffers each having an input and an output.
Claim 6
Dependent Claim
26 words
The column amplifier of claim 4, further comprising a differential amplifier for amplifying the difference between the outputs of the two buffers of the buffer stage.
Claim 7
Dependent Claim
154 words
A column amplifier for use in an image sensor, said image sensor including a plurality of pixels organized into rows and columns, at least one of said columns having the signals from its pixels carried by a bit line for further signal processing, said column amplifier comprising: (a) an operational amplifier with an inverting input, a noninverting input, and an output; (b) an input capacitor coupled between the bit line and one of the inputs of the operational amplifier; (c) a feedback capacitor coupled directly in a feedback path between one of the inputs of the operational amplifier and the output of the operational amplifier; and (d) a switch between said input of the signal amplifier and said output of the signal amplifier, said switch being in parallel with said feedback capacitor to selectively bypass said feedback capacitor; wherein no other electrically active element other than said feedback capacitor is in said feedback path.
Claim 8
Dependent Claim
154 words
A column amplifier for use in an image sensor, said image sensor including a plurality of pixels organized into rows and columns, at least one of said columns having the signals from its pixels carried by a bit line for further signal processing, said column amplifier comprising: (a) an operational amplifier with an inverting input, a noninverting input, and an output; (b) an input capacitor coupled between the bit line and one of the inputs of the operational amplifier; (c) a feedback capacitor coupled directly in a feedback path between one of the inputs of the operational amplifier and the output of the operational amplifier; and (d) a switch between said input of the signal amplifier and said output of the signal amplifier, said switch being in parallel with said feedback capacitor to selectively bypass said feedback capacitor; wherein no other electrically active element other than said feedback capacitor is in said feedback path.
Claim 9
Dependent Claim
36 words
The column amplifier of claim 6, further comprising a sample and hold stage coupled to the output of the operational amplifier, the sample and hold stage having at least one input and at least one output.
Claim 10
Dependent Claim
21 words
The column amplifier of claim 7, further comprising a buffer stage coupled to an output of the sample and hold stage.
Claim 11
Dependent Claim
32 words
The column amplifier of claim 8, wherein the sample and hold stage includes at least two signal lines with at least one sampling capacitor coupled to each of the two signal lines.
Claim 12
Dependent Claim
30 words
The column amplifier of claim 9, wherein the buffer stage includes at least two signal lines with at least one output buffer coupled to each of the two signal lines.
Claim 13
Independent Claim
51 words
A method for amplifying signals from a bit line from a column of an image sensor, the method comprising: (a) adjusting the common mode offset in the image signals from the bit line to produce adjusted image signals; and (b) amplifying the adjusted image signals to produce amplified adjusted image signals.
Claim 14
Independent Claim
51 words
A method for amplifying signals from a bit line from a column of an image sensor, the method comprising: (a) adjusting the common mode offset in the image signals from the bit line to produce adjusted image signals; and (b) amplifying the adjusted image signals to produce amplified adjusted image signals.
Claim 15
Dependent Claim
19 words
The method of claim 11, further comprising further processing the amplified image signals through a sample and hold stage.
Claim 16
Dependent Claim
38 words
The method of claim 12, wherein the processing of the amplified adjusted image signals through the sample and hold stage includes storing a signal voltage level on a first capacitor and reference voltage level on a second capacitor.
Claim 17
Dependent Claim
18 words
The method of claim 13, further comprising further processing the amplified adjusted image signals through a buffer stage.
Claim 18
Dependent Claim
24 words
The method of claim 14, further comprising amplifying the difference between the signal voltage level and the reference voltage level after the buffer stage.
Claim 19
Dependent Claim
31 words
The method of claim 11, wherein the adjustment of the common mode offset is accomplished through use of a switching capacitor amplifier in which the common mode offset may be adjusted.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-10-03 | 2004-04-03 | 2004-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-03 | 2008-04-03 | 2008-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-03 | 2012-04-03 | 2012-10-03 | $7700.00 | Window Closed / Lapsed |