Patent US5335015A successfully refreshed from Google Patents.
US5335015A
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US
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Method for improved dynamic range of BCMD image sensors
Assignee: Texas Instruments Inc
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Filing: 1992-10-30
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Granted: 1994-08-02
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Expires: 2012-10-30
Abstract
Abstract The dynamic range of an image array photosite is improved by, first, turning on a column clamp transistor having a source coupled to a photosite transistor source and a drain coupled to a photosite transistor drain, wherein the column clamp transistor is turned on by a column clamp transistor gate voltage; then decreasing a current supplied to a column sense line below a quiescent value, wherein the column sense line is coupled to the photosite transistor source; then turning on the photosite transistor by a photosite transistor gate voltage; then turning off the photosite transistor and the column clamp transistor at substantially the same time; then increasing the current above the quiescent value; and then returning the current to the quiescent value.
Inventors
- 👤 Alan N. Cooper
- 👤 William P. McCracken
- 👤 Jaroslav Hynecek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:55
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/60; H04N25/62; H04N25/621; H04N25/70; H04N25/76
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
119 words
A method for improving the dynamic range of an image array photosite, comprising the steps of: turning on a column clamp transistor having a source coupled to a photosite transistor source and a drain coupled to a photosite transistor drain, said column clamp transistor is turned on by a column clamp transistor gate voltage; decreasing a current supplied to a column sense line below a quiescent value, said column sense line is coupled to said photosite transistor source; turning on said photosite transistor by a photosite transistor gate voltage; turning off said photosite transistor and said column clamp transistor at substantially the same time; increasing said current above said quiescent value; and returning said current to said quiescent value.
Claim 2
Independent Claim
119 words
A method for improving the dynamic range of an image array photosite, comprising the steps of: turning on a column clamp transistor having a source coupled to a photosite transistor source and a drain coupled to a photosite transistor drain, said column clamp transistor is turned on by a column clamp transistor gate voltage; decreasing a current supplied to a column sense line below a quiescent value, said column sense line is coupled to said photosite transistor source; turning on said photosite transistor by a photosite transistor gate voltage; turning off said photosite transistor and said column clamp transistor at substantially the same time; increasing said current above said quiescent value; and returning said current to said quiescent value.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein said returning step is performed before a source voltage of said photosite transistor source exceeds zero volts relative to ground.
Claim 4
Dependent Claim
35 words
The method of claim 1 wherein the current supplied to the column sense line is decreased by increasing a control voltage that controls the current, and the current is increased by lowering the control voltage.
Claim 5
Dependent Claim
15 words
The method of claim 3 wherein the control voltage is provided by a digital implementation.
Claim 6
Dependent Claim
15 words
The method of claim 3 wherein the control voltage is provided by an analog implementation.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the control voltage is generated by applying the column clamp transistor gate voltage through a capacitor.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the photosite transistor is a P-type buried channel MOS transistor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-01 | 1998-01-31 | 1998-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-01 | 2002-01-31 | 2002-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-01 | 2006-01-31 | 2006-08-02 | $7700.00 | Window Closed / Lapsed |