US3668545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for amplifier protection
Assignee: H H SCOTT Inc
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Filing: 1969-11-03
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Granted: 1972-06-06
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Expires: 1989-11-03
Abstract
Abstract Protection for amplifiers and the like is provided by proportionally combining a measure of the voltage across the output terminals with a measure of the output current and actuating switching means across the input terminals when a proportional combination exceeds a predetermined value. Transistors may be employed as the amplifier and switching means, and push-pull amplifiers may be so protected. In one embodiment a current-responsive protection device protects both transistors of a push-pull circuit. Multiple proportioning ranges may be provided in a non-linear protection arrangement, and the protection device may be rendered insensitive to short duration overloads. Reverse current protection may also be provided by the addition of one or more diodes.
Inventors
- 👤 Daniel R Von Recklinghausen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:36
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; G; G06; G06G; G06G7/00; G06G7/12; G06G7/26; G06G7/28
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
155 words
In combination, an amplifier having a pair of input terminals and a pair of output terminals, a voltage supply having supply terminals connected to said output terminals, respectively, a source of signals having signal terminals connected to said input terminals, respectively, and means for protecting said amplifier, said protecting means comprising switching means connected between said signal terminals and adapted, when actuated, to provide a conductive path between said signal terminals, first means including a connection to one of said output terminals for deriving a first electrical response dependent upon the voltage across said output terminals, second means including a connection to the other of said output terminals for deriving a second electrical response dependent upon the current passed through said amplifier between said output terminals, and third means connected to said first and second means for proportionally combining said responses and for actuating said switching means when a proportional combination exceeds a predetermined value.
Claim 2
Dependent Claim
155 words
In combination, an amplifier having a pair of input terminals and a pair of output terminals, a voltage supply having supply terminals connected to said output terminals, respectively, a source of signals having signal terminals connected to said input terminals, respectively, and means for protecting said amplifier, said protecting means comprising switching means connected between said signal terminals and adapted, when actuated, to provide a conductive path between said signal terminals, first means including a connection to one of said output terminals for deriving a first electrical response dependent upon the voltage across said output terminals, second means including a connection to the other of said output terminals for deriving a second electrical response dependent upon the current passed through said amplifier between said output terminals, and third means connected to said first and second means for proportionally combining said responses and for actuating said switching means when a proportional combination exceeds a predetermined value.
Claim 3
Dependent Claim
29 words
A combination as set forth in claim 1, further comprising time constant means for preventing actuation of said switching means when said responses are less than of predetermined duration.
Claim 4
Dependent Claim
31 words
A combination as set forth in claim 1 and in which said combining means comprises means for producing differenT proportional combinations for different ranges of values of one of said responses.
Claim 5
Dependent Claim
51 words
A combination as set forth in claim 1 and in which said switching means comprises means for by-passing from said input terminals only that portion of amplifier driving signals at said signal terminals which is substantially in excess of a driving signal amplitude that causes said switching means to be actuated.
Claim 6
Dependent Claim
89 words
A combination as set forth in claim 1 and in which said amplifier comprises first transistor means having base, collector and emitter electrode means, the switching means comprises a normally non-conductive further transistor means having base, collector and emitter electrode means two of which electrode means are connected to said input terminals to enable conduction there-across, the said response deriving and combining means comprising resistance means connected to the collector and emitter electrode means of the first transistor means and the base electrode means of the further transistor means.
Claim 7
Dependent Claim
50 words
A combination as set forth in claim 5 and in which said resistance means comprises a pair of resistors one of which is an emitter load of the first transistor means and the other of which is connected between the collector and emitter electrode means of the first transistor means.
Claim 8
Dependent Claim
31 words
A combination as set forth in claim 6 and in which said emitter load resistor is connected to the base electrode means of the further transistor means by a further resistor.
Claim 9
Dependent Claim
39 words
A combination as set forth in claim 7 and in which said base electrode means of the first transistor means and said emitter load resistor are connected to the collector and emitter electrode means of the further transistor means.
Claim 10
Dependent Claim
23 words
A combination as set forth in claim 7 and in which the said first transistor means comprises a pair of successively connected transistors.
Claim 11
Dependent Claim
45 words
A combination as set forth in claim 7 and in which a voltage source is connected to the base electrode means of the further transistor means for establishing a voltage which affects the operating point at which said further transistor means may be rendered conductive.
Claim 12
Dependent Claim
17 words
A combination as set forth in claim 10 and in which said voltage source comprises diode means.
Claim 13
Dependent Claim
16 words
A combination as set forth in claim 6 in which said other resistor is substantially linear.
Claim 14
Dependent Claim
54 words
A combination as set forth in claim 5 and in which the resistance means connected to the collector electrode means of the first transistor means and the base electrode means of the further transistor means comprises a plurality of non-linear resistive networks providing successively different proportional combinations for rendering the further transistor means conductive.
Claim 15
Dependent Claim
28 words
A combination as set forth in claim 5 and in which reverse-conduction-preventing diode means is connected in series with the collector electrode means of the first transistor means.
Claim 16
Dependent Claim
28 words
A combination as set forth in claim 5 and in which reverse-conduction-preventing diode means is connected between the collector and emitter electrode means of the first transistor means.
Claim 17
Dependent Claim
40 words
A combination as set forth in claim 1, there being a pair of said amplifiers connected to said signal terminals and said voltage supply in a push-pull Class B circuit, each amplifier being provided with one of said protecting means.
Claim 18
Dependent Claim
102 words
A combination as set forth in claim 1 and in which said amplifier comprises a first transistor having base, emitter, and collector electrodes and said switching means comprises a second transistor having base, emitter, and collector electrodes, said input terminals being connected to said base and emitter electrodes of said first transistor, respectively, said emitter and collector electrodes of said second transistor being connected to said signal terminals, respectively, and said current-response-deriving means comprising an emitter load resistor connected to the emitter electrode of said first transistor and connected to the base electrode of said second traNsistor through a voltage threshold device.
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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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |