US4484148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current source frequency compensation for a CMOS amplifier
Assignee: National Semiconductor Corp
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Filing: 1982-09-13
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Granted: 1984-11-20
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Expires: 2002-09-13
Abstract
Abstract A CMOS linear amplifier is disclosed with a frequency compensation circuit that employs a Miller integrater construction in which the feedback capacitor is coupled by way of a noninverting amplifier operating at constant current and therefore does not load the inverting amplifier input or bypass the integrator amplifier.
Inventors
- 👤 James B. Wieser
- 👤 Ray A. Reed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:11
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/08; H03F1/083; H03F1/086; H03F3/00; H03F3/30; H03F3/3001
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
103 words
A CMOS linear signal amplifier frequency compensation circuit comprising: an inverting amplifier having input and output terminals; a frequency compensation capacitor coupled between said input and output terminals; and a current feedback element coupled in series with said capacitor wherein said current feedback element comprises a common gate transistor amplifier having an input source coupled to said capacitor and an output drain coupled to said input of said inverting amplifier whereby said capacitor is coupled from said inverting amplifier output to said inverting amplifier input thereby providing compensation but said capacitor does not act as a capacitive load at said inverting amplifier input.
Claim 2
Dependent Claim
103 words
A CMOS linear signal amplifier frequency compensation circuit comprising: an inverting amplifier having input and output terminals; a frequency compensation capacitor coupled between said input and output terminals; and a current feedback element coupled in series with said capacitor wherein said current feedback element comprises a common gate transistor amplifier having an input source coupled to said capacitor and an output drain coupled to said input of said inverting amplifier whereby said capacitor is coupled from said inverting amplifier output to said inverting amplifier input thereby providing compensation but said capacitor does not act as a capacitive load at said inverting amplifier input.
Claim 3
Dependent Claim
24 words
The circuit of claim 1 wherein said common gate transistor amplifier includes a constant current biasing device coupled in series with its source electrode.
Claim 4
Dependent Claim
29 words
The circuit of claim 2 wherein said inverting amplifier is driven from a differential input stage having a single ended output coupled to said input of said inverting amplifier.
Claim 5
Dependent Claim
19 words
The circuit of claim 3 further comprising a dummy current feedback element coupled to balance said differential input stage.
Claim 6
Dependent Claim
23 words
The circuit of claim 3 wherein said common gate transistor amplifier is incorporated into said input stage as a cascode connected driver transistor.
Claim 7
Dependent Claim
23 words
The circuit of claim 5 wherein said differential input stage further acts as said constant current device for said common gate transistor amplifier.
Claim 8
Dependent Claim
22 words
The circuit of claim 6 wherein a dummy cascode load transistor is included in said differential input stage to balance its operation.
References Cited (Backward Citations)
US4315223A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |