US4910516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated dual-slope analog to digital converter with R/C variance compensation
Assignee: Texas Instruments Inc
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Filing: 1989-04-27
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Granted: 1990-03-20
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Expires: 2009-04-27
Abstract
Abstract A dual-slope A/D converter circuit has an oscillator (14) whose timing frequency is determined by the value of an oscillator resistor (70) and a oscillator capacitor (72). An integrator (66) integrates an input voltage at a rate determined by an integrating resistor (64) and an integrating capacitor (68). The oscillator resistor (70) and integrator resistor (64) are designed such that their ratio will remain constant despite variations in actual value due to manufacturing inaccuracies. The oscillator capacitor (72) and integrating capacitor (68) are similarly designed. Consequently, an optimum peak integration value can be obtained at full scale input despite variations in actual resistive and capacitive values.
Inventors
- 👤 William R. Krenik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:27
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/06; H03M1/0617; H03M1/0619; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
118 words
A method of forming an integrated analog-to-digital converter comprising the steps of: forming an integrator having a first resistor and a first capacitor; forming an oscillator having a second resistor and a second capacitor; said first and second resistors formed such that any variation from desired values effects both first and second resistor values proportionally, resulting in a substantially fixed defined ratio between said first and second resistors; and said first and second capacitors formed such that any variation from desired values effects both first and second capacitor values proportionally, resulting in a substantially fixed defined ratio between said first and second capacitors wherein said fixed defined ratios result in a predetermined maximum output voltage of said integrator.
Claim 2
Independent Claim
118 words
A method of forming an integrated analog-to-digital converter comprising the steps of: forming an integrator having a first resistor and a first capacitor; forming an oscillator having a second resistor and a second capacitor; said first and second resistors formed such that any variation from desired values effects both first and second resistor values proportionally, resulting in a substantially fixed defined ratio between said first and second resistors; and said first and second capacitors formed such that any variation from desired values effects both first and second capacitor values proportionally, resulting in a substantially fixed defined ratio between said first and second capacitors wherein said fixed defined ratios result in a predetermined maximum output voltage of said integrator.
Claim 3
Dependent Claim
39 words
The method of claim 1 and further comprising the step of forming said first and second resistors are within 30×10 -3 inches of each other, such that each resistor has the same ratio of actual value to desired value.
Claim 4
Dependent Claim
35 words
The method of claim 1 and further comprising the step of forming said first and second capacitors within a predetermined distance such that each capacitor has the same ratio of actual value to desired value.
Claim 5
Dependent Claim
43 words
The method of claim 1 and further comprising forming the plates of said first and second capacitors such that the bottom plates of the capacitors are formed a first layer and the top plates of the capacitors are formed on a second layer.
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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) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |