US4405900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Operational amplifier
Assignee: US Philips Corp
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Filing: 1981-04-08
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Granted: 1983-09-20
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Expires: 2001-04-08
Abstract
Abstract An operational amplifier having a first amplifier stage and a second amplifier stage, which is driven by the first amplifier stage. According to the invention such an operational amplifier can be corrected for high frequencies in a very simple and effective manner by including a capacitance in parallel with the second amplifier stage between an output of the first stage and an output of the second stage which is comparatively high-ohmic relative to said output of the first stage. The second stage, which is bypassed by said capacitance, is then non-inverting for the part bypassed by said capacitance.
Inventors
- 👤 Rudy J. VAN DE Plassche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:47
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/08; H03F1/083; H03F1/42; H03F1/48; H03F3/00; H03F3/189; H03F3/19; H03F3/195
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
129 words
An operational amplifier comprising at least a first amplifier stage, a second amplifier stage, which is driven by the first amplifier stage, and a first and a second junction point between which a capacitive signal path, for improving the high-frequency properties of the operational amplifier, is included characterized in that the first junction point is coupled to an output of the first amplifier stage and that the second junction point is coupled to an output of the second amplifier stage, the capacitive signal path, relative to the signal path via the second amplifier stage, constituting a positive feed-forward and the impedance at the second junction point, viewed from said capacitive signal path, being comparatively high-relative to the impedance at the first junction point, viewed from said capacitive signal path.
Claim 2
Dependent Claim
129 words
An operational amplifier comprising at least a first amplifier stage, a second amplifier stage, which is driven by the first amplifier stage, and a first and a second junction point between which a capacitive signal path, for improving the high-frequency properties of the operational amplifier, is included characterized in that the first junction point is coupled to an output of the first amplifier stage and that the second junction point is coupled to an output of the second amplifier stage, the capacitive signal path, relative to the signal path via the second amplifier stage, constituting a positive feed-forward and the impedance at the second junction point, viewed from said capacitive signal path, being comparatively high-relative to the impedance at the first junction point, viewed from said capacitive signal path.
Claim 3
Dependent Claim
29 words
An operational amplifier as claimed in claim 1, characterized in that said output of the first amplifier stage is connected to the first junction point via a voltage follower.
Claim 4
Dependent Claim
31 words
An operational amplifier as claimed in claim 2, characterized in that said output of the first amplifier stage, in addition, is connected directly to an input of the second amplifier stage.
Claim 5
Dependent Claim
41 words
An operational amplifier as claimed in claim 3, characterized in that a further input of the second amplifier stage is coupled to an output of the first amplifier stage other than the output to which the first junction point is coupled.
Claim 6
Dependent Claim
28 words
An operational amplifier as claimed in claim 1 or 2, characterized in that an input of the second amplifier stage is connected directly to the first junction point.
Claim 7
Dependent Claim
41 words
An operational amplifier as claimed in claim 5, characterized in that a further input of the second amplifier stage is coupled to an output of the first amplifier stage other than the output to which the first junction point is coupled.
Claim 8
Dependent Claim
41 words
An operational amplifier as claimed in claim 1 or 2, characterized in that an input of the second amplifier stage is coupled to an output of the amplifier stage other than the output to which the first junction point is coupled.
Claim 9
Dependent Claim
35 words
An operational amplifier as claimed in claim 1, characterized in that the second junction point is coupled directly to that output of the second amplifier stage which leads to an output of the operational amplifier.
Claim 10
Dependent Claim
93 words
An operational amplifier as claimed in claim 1, characterized in that said operational amplifier further comprises a third amplifier stage whose gain is substantially smaller but whose maximum output current variation per unit of time is substantially greater than that of the second amplifier stage, one or more inputs of the third amplifier stage being coupled to one or more outputs of the first amplifier stage in such a way that the signal path via the third amplifier stage realtive to the signal path via the second amplifier stage constitutes a positive feed-forward.
References Cited (Backward Citations)
US3408586A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-19 | 1987-03-21 | 1987-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-19 | 1991-03-21 | 1991-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-19 | 1995-03-21 | 1995-09-20 | $7700.00 | Window Closed / Lapsed |