Patent US6532040B1 successfully refreshed from Google Patents.
US6532040B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-noise active-pixel sensor for imaging arrays with high speed row reset
Assignee: Re Secured Networks LLC
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Filing: 1998-09-09
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Granted: 2003-03-11
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Expires: 2018-09-09
Abstract
Abstract An imager pixel including a photodetector, a first MOS transistor functioning as the driver of a source follower amplifier during signal readout, a second MOS transistor serving as a pixel readout transistor, a third MOS transistor serving as a photodetector reset transistor, and a reset noise cancellation circuit including a fourth MOS transistor, first and second capacitances, and an amplifier having a gain which is the inverse of the ratio of the first to the second capacitance.
Inventors
- 👤 Lester J. Kozlowski
- 👤 David L. Standley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:47
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/04; H03F3/08; H03F3/087; H04; H04N; H04N25/00; H04N25/60; H04N25/65; H04N25/70; H04N25/76; H04N25/77; H04N25/771; H04N25/78
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
59 words
An active pixel circuit having a photodetector, a source follower driver transistor, a row select transistor, a reset transistor, and a fourth transistor, the circuit comprising: a first capacitance connected between a node formed by the fourth transistor and the reset transistor and a circuit ground; and a second capacitance connected between the reset transistor and the fourth transistor.
Claim 2
Dependent Claim
59 words
An active pixel circuit having a photodetector, a source follower driver transistor, a row select transistor, a reset transistor, and a fourth transistor, the circuit comprising: a first capacitance connected between a node formed by the fourth transistor and the reset transistor and a circuit ground; and a second capacitance connected between the reset transistor and the fourth transistor.
Claim 3
Dependent Claim
38 words
The circuit of claim 1 , further comprising a feedback amplifier connected between the row select transistor and the fourth transistor, wherein the gain of the amplifier equals a ratio of the first capacitance to the second capacitance.
Claim 4
Dependent Claim
18 words
The circuit of claim 2 , wherein the feedback amplifier reduces reset noise caused by resetting the photodetector.
Claim 5
Dependent Claim
10 words
The circuit of claim 3 wherein the transistors are MOSFETs.
Claim 6
Dependent Claim
14 words
The circuit of claim 4 , wherein the each MOSFET is fabricated in CMOS.
Claim 7
Dependent Claim
19 words
The circuit of claim 5 , wherein the photodetector comprises a substrate diode with a silicide portion thereof removed.
Claim 8
Dependent Claim
20 words
The circuit of claim 1 , wherein the first capacitance is formed by the gate-to-diffusion overlap of the fourth transistor.
Claim 9
Dependent Claim
19 words
The circuit of claim 1 wherein the second capacitance comprises a first interconnect layer overlapping a second interconnect layer.
Claim 10
Dependent Claim
16 words
The circuit of claim 8 , wherein the second interconnect layer is a photodiode interconnect layer.
Claim 11
Dependent Claim
126 words
An active pixel sensor circuit comprising: (a) a photodetector element having a node; (b) a first transistor having a control leg connected to the node and second and third legs, the third leg being connected to a power supply voltage; (c) a second transistor having a control leg and fourth and fifth legs, the fourth leg connected to the second leg of the first transistor; (d) a third transistor having a control leg and sixth and seventh legs, the seventh leg being connected to a reset voltage source; (e) a fourth transistor having a control leg and eighth and ninth legs; (f) a first capacitance formed between the eighth leg and ground; and (g) a second capacitance formed between the eighth leg and the sixth leg.
Claim 12
Dependent Claim
126 words
An active pixel sensor circuit comprising: (a) a photodetector element having a node; (b) a first transistor having a control leg connected to the node and second and third legs, the third leg being connected to a power supply voltage; (c) a second transistor having a control leg and fourth and fifth legs, the fourth leg connected to the second leg of the first transistor; (d) a third transistor having a control leg and sixth and seventh legs, the seventh leg being connected to a reset voltage source; (e) a fourth transistor having a control leg and eighth and ninth legs; (f) a first capacitance formed between the eighth leg and ground; and (g) a second capacitance formed between the eighth leg and the sixth leg.
Claim 13
Dependent Claim
34 words
The circuit of claim 10 further including an amplifier having an output connected to the ninth leg, the amplifier having a gain equal to a ratio of the first capacitance to the second capacitance.
Claim 14
Dependent Claim
18 words
The circuit of claim 11 , wherein the feedback amplifier reduces reset noise caused by resetting the photodetector.
Claim 15
Dependent Claim
18 words
The apparatus of claim 12 wherein each of the first, second, third and fourth transistors comprises a MOSFET.
Claim 16
Dependent Claim
13 words
The apparatus of claim 13 wherein each the MOSFET is fabricated in CMOS.
Claim 17
Dependent Claim
18 words
The apparatus of claim 14 wherein the photodetector comprises a substrate diode with a silicide portion thereof removed.
Claim 18
Dependent Claim
23 words
The apparatus of claim 10 wherein the second capacitance comprises an overlapping portion of the node and an interconnect layer of the diode.
Claim 19
Dependent Claim
19 words
The apparatus of claim 10 wherein the second capacitance comprises a first interconnect layer overlapping a second interconnect layer.
Claim 20
Dependent Claim
15 words
The apparatus of claim 17 wherein the second interconnect layer is a photodiode interconnect layer.
Claim 21
Dependent Claim
19 words
The apparatus of claim 14 wherein the photodetector comprises an n on p photodiode junction in a p-type substrate.
Claim 22
Dependent Claim
19 words
The apparatus of claim 14 wherein the photodetector comprises a p on n photodiode junction in an n-type substrate.
Claim 23
Dependent Claim
99 words
In an active pixel circuit including a photodetector, a source follower driver MOS transistor, a row select MOS transistor, a reset MOS transistor, a fourth MOS transistor, a method for reducing reset noise, the method comprising: arranging a first and second capacitances to apply a ratio of the values thereof to a voltage on one of them; reading out the voltage on the photodetector; resetting the photodetector; and canceling reset noise created by resetting the photodetector by applying a gain which is the inverse of the ratio to generate a noise cancellation signal for supply to the fourth transistor.
Claim 24
Dependent Claim
99 words
In an active pixel circuit including a photodetector, a source follower driver MOS transistor, a row select MOS transistor, a reset MOS transistor, a fourth MOS transistor, a method for reducing reset noise, the method comprising: arranging a first and second capacitances to apply a ratio of the values thereof to a voltage on one of them; reading out the voltage on the photodetector; resetting the photodetector; and canceling reset noise created by resetting the photodetector by applying a gain which is the inverse of the ratio to generate a noise cancellation signal for supply to the fourth transistor.
Claim 25
Dependent Claim
34 words
The method of claim 21 wherein the step of reading out the voltage on the photodetector includes the step of holding off the reset MOS transistor and tuning on the row select MOS transistor.
Claim 26
Dependent Claim
22 words
The method of claim 22 wherein the step of resetting the photodetector comprises the step of fully enabling the reset MOS transistor.
Claim 27
Dependent Claim
34 words
The method of claim 22 wherein the step of reading out the voltage further includes the step of programming a feedback amplifier to a gain selected to provide desired signal sensitivity for optimum imaging.
Claim 28
Dependent Claim
30 words
The method of claim 21 wherein the step of canceling reset noise includes the step of setting a gain of a feedback amplifier equal to the inverse of the ratio.
Claim 29
Dependent Claim
34 words
The method of claim 25 wherein the step of reading out the voltage further includes the step of programming the feedback amplifier to a gain selected to provide desired signal sensitivity for optimum imaging.
Claim 30
Dependent Claim
38 words
The method of claim 25 wherein the step of canceling the reset noise further comprises the step of enabling the fourth transistor to close a feedback loop to the first capacitance, the feedback loop including the feedback amplifier.
Claim 31
Dependent Claim
20 words
The method of claim 27 wherein the second capacitance supplies a normalizing signal to an integrating node of the photodiode.
Claim 32
Dependent Claim
17 words
The method of claim 27 further including the step of canceling offset created by the feedback amplifier.
Claim 33
Dependent Claim
69 words
In an imager pixel including a photodetector having a node and further having first, second, third and fourth transistors, a method of improving performance comprising: creating a first and second capacitances in the pixel adjacent to the node, the first and second capacitances having a ratio; and employing an amplifier having a gain which is the inverse of the ratio to cancel reset noise resulting from resetting the photodetector.
Claim 34
Dependent Claim
69 words
In an imager pixel including a photodetector having a node and further having first, second, third and fourth transistors, a method of improving performance comprising: creating a first and second capacitances in the pixel adjacent to the node, the first and second capacitances having a ratio; and employing an amplifier having a gain which is the inverse of the ratio to cancel reset noise resulting from resetting the photodetector.
Claim 35
Dependent Claim
16 words
The method of claim 30 wherein the first, second, third and fourth transistors comprise MOS transistors.
Claim 36
Dependent Claim
89 words
An imager pixel comprising: a photodetector; first and second capacitances adjacent the photodetector and connected so as to supply a voltage on the first capacitance to the photodetector while multiplying that voltage by the ratio of the second capacitance to the first capacitance; a first transistor means for functioning as the driver of a source follower amplifier during signal readout; second transistor means for controlling signal readout; third transistor means for serving as a reset switch; and a fourth transistor means for transferring a voltage to the first capacitance.
Claim 37
Dependent Claim
89 words
An imager pixel comprising: a photodetector; first and second capacitances adjacent the photodetector and connected so as to supply a voltage on the first capacitance to the photodetector while multiplying that voltage by the ratio of the second capacitance to the first capacitance; a first transistor means for functioning as the driver of a source follower amplifier during signal readout; second transistor means for controlling signal readout; third transistor means for serving as a reset switch; and a fourth transistor means for transferring a voltage to the first capacitance.
Claim 38
Dependent Claim
16 words
The imager pixel of claim 32 and further including a feedback circuit for generating the voltage.
Claim 39
Dependent Claim
22 words
The invention of claim 33 wherein the feedback circuit includes an amplifier having a gain which is the inverse of the ratio.
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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) | 2006-03-10 | 2006-09-09 | 2007-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-03-10 | 2010-09-09 | 2011-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-03-10 | 2014-09-09 | 2015-03-11 | $7700.00 | Window Closed / Lapsed |