US3988693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Complementary push-pull amplifier device with protective circuit means
Assignee: Hitachi Ltd
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Filing: 1975-05-21
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Granted: 1976-10-26
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Expires: 1995-05-21
Abstract
Abstract In an amplifier device including a driving amplifier circuit and a push-pull output circuit, the push-pull output circuit consisting of a first amplifier portion which turns "on" when the drive current of the driving amplifier circuit decreases, and a second amplifier portion which turns "on" when the drive current increases, the improvement comprising the first protective circuit which is disposed on the input side of the first amplifier portion so as to branch an input current when the first amplifier portion falls outside its allowable operating range, and the second protective circuit which is disposed on the input side of the driving amplifier circuit so as to branch an input current when the second amplifier portion falls outside its allowable operating range, whereby even when the drive current of the driving amplifier circuit becomes large, the constituent parts of the push-pull output circuit can be reliably protected from being destroyed.
Inventors
- 👤 Kunio Seki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:43
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; H03F3/00; H03F3/20; H03F3/21; H03F3/213; H03F3/30; H03F3/3083; H03F3/3086; H03F3/3091
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
270 words
In a complementary push-pull amplifier device with protective circuit means including at least a driving amplifier circuit and a push-pull output circuit connected to the output of said driving amplifier circuit, the push-pull output circuit consisting of a first amplifier portion and a second amplifier portion, wherein inputs of said first and second amplifier portions are respectively connected to the output of said driving amplifier circuit, so that said first amplifier portion is rendered conductive and said second amplifier portion is rendered non-conductive respectively when the drive current of said driving amplifier circuit decreases, and said first amplifier portion is rendered non-conductive and said second amplifier portion is rendered conductive when the drive current of said driving amplifier circuit increases, the improvement comprising: a first detecting circuit connected in series with said first amplifier portion between a first d.c. voltage source and an output juncture of said push-pull output circuit; a second detecting circuit connected in series with said second amplifier portion between said output juncture of said push-pull output circuit and a second d.c. voltage source; first protective circuit means, connected to the input of said first amplifier portion and responsive to a first detected signal of said first detecting circuit, for controlling the input of said first amplifier portion, when said first amplifier portion falls out of its allowable operating range; and second protective circuit means, connected to the input of said driving amplifier circuit and responsive to a second detected signal of said second detecting circuit, for controlling the input of said second amplifier portion when said second amplifier portion falls out of its allowable operating range.
Claim 2
Dependent Claim
270 words
In a complementary push-pull amplifier device with protective circuit means including at least a driving amplifier circuit and a push-pull output circuit connected to the output of said driving amplifier circuit, the push-pull output circuit consisting of a first amplifier portion and a second amplifier portion, wherein inputs of said first and second amplifier portions are respectively connected to the output of said driving amplifier circuit, so that said first amplifier portion is rendered conductive and said second amplifier portion is rendered non-conductive respectively when the drive current of said driving amplifier circuit decreases, and said first amplifier portion is rendered non-conductive and said second amplifier portion is rendered conductive when the drive current of said driving amplifier circuit increases, the improvement comprising: a first detecting circuit connected in series with said first amplifier portion between a first d.c. voltage source and an output juncture of said push-pull output circuit; a second detecting circuit connected in series with said second amplifier portion between said output juncture of said push-pull output circuit and a second d.c. voltage source; first protective circuit means, connected to the input of said first amplifier portion and responsive to a first detected signal of said first detecting circuit, for controlling the input of said first amplifier portion, when said first amplifier portion falls out of its allowable operating range; and second protective circuit means, connected to the input of said driving amplifier circuit and responsive to a second detected signal of said second detecting circuit, for controlling the input of said second amplifier portion when said second amplifier portion falls out of its allowable operating range.
Claim 3
Dependent Claim
32 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 1, wherein said first and second amplifier portions each comprises a respective pair of transistors in the Darlington connection.
Claim 4
Dependent Claim
32 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 1, wherein said first and second amplifier portions each comprise a respective pair of transistors of the complementary type.
Claim 5
Dependent Claim
66 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 1, wherein said first protective circuit means comprises a first transistor connected between the input of said first amplifier portion and said output juncture of said push-pull circuit, and said second protective circuit means comprises a second transistor connected between the input of said driving amplifier circuit and said second d.c. voltage source.
Claim 6
Dependent Claim
29 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 4, further including a differential amplifier circuit connected to the input of said driving amplifier circuit.
Claim 7
Dependent Claim
42 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 4, wherein a constant current source is connected to the output of said driving amplifier circuit which is connected to the inputs of said first and second amplifier portions.
Claim 8
Dependent Claim
29 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 6, further including a differential amplifier circuit connected to the input of said driving amplifier circuit.
Claim 9
Dependent Claim
28 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 4, wherein said driving amplifier circuit comprises a pair of transistors connected in Darlington configuration.
Claim 10
Dependent Claim
29 words
A complementary push-pull amplifier device with protective circuit means as defined in claim 8, wherein a level shift circuit is connected to the input of said driving amplifier circuit.
Claim 11
Dependent Claim
53 words
A complementary push-pull amplifier device as defined in claim 1, wherein each one of said driving amplifier circuit and said first amplifier portion comprises at least one transistor of a first conductivity type, and said second amplifier portion comprises at least one transistor of a second conductivity type, opposite said first conductivity type.
Claim 12
Dependent Claim
30 words
A complementary push-pull amplifier device as defined in claim 10, wherein each of said first and second protective circuit means comprises at least one transistor of said first conductivity type.
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) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |