Patent US3686580A successfully refreshed from Google Patents.
US3686580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current amplifier
Assignee: US Philips Corp
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Filing: 1970-09-17
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Granted: 1972-08-22
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Expires: 1990-09-17
Abstract
Abstract A current amplifier comprising first and second series circuits coupled to the emitter and base respectively of a first transistor amplifying received signals to allow accurate adjustment of the current in the first series circuit relative to the current in the second series circuit without increasing the output impedance of the amplifier. The first series circuit comprises a first diode and a second transistor coupling the emitter of the first transistor to the power supply. The second series circuit comprises a second diode, a third transistor, and a current determining means coupling the base of the first transistor to the power supply. The first and second series circuits cooperate to respond to differences in the current between the current in the second series circuit and the current in the first series circuit thereby maintaining predetermined relationships between these currents.
Inventors
- 👤 Rudy Johan Van Den Plassche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:07
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3069; H03F3/3071; H03F3/3066; H03F3/3067
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
210 words
A current amplifier comprising signal input and output means, a first transistor for amplifying received signals having its base coupled to said signal input means and its emitter coupled to said signal output means, input means for a power supply, the collector of said first transistor being connected to a first terminal of said power supply input means, a first series circuit coupling the emitter of said first transistor to a second terminal of said power supply input means, said first series circuit comprising a first diode and the emitter-collector path of a second transistor, a second series circuit coupling the base of said first transistor to said second terminal of said power supply, said second series circuit comprising a second diode, the emitter-collector path of a third transistor and current determining means, the base of said third transistor being connected to the junction between said first diode and said second transistor and the base of said second transistor being connected to the junction between said third transistor and said current determining means, said first and second series circuits providing means for measuring and adjustIng the current in said first series circuit in response to deviations thereof to maintain predetermined current relationships with the current in said second series circuit.
Claim 2
Dependent Claim
210 words
A current amplifier comprising signal input and output means, a first transistor for amplifying received signals having its base coupled to said signal input means and its emitter coupled to said signal output means, input means for a power supply, the collector of said first transistor being connected to a first terminal of said power supply input means, a first series circuit coupling the emitter of said first transistor to a second terminal of said power supply input means, said first series circuit comprising a first diode and the emitter-collector path of a second transistor, a second series circuit coupling the base of said first transistor to said second terminal of said power supply, said second series circuit comprising a second diode, the emitter-collector path of a third transistor and current determining means, the base of said third transistor being connected to the junction between said first diode and said second transistor and the base of said second transistor being connected to the junction between said third transistor and said current determining means, said first and second series circuits providing means for measuring and adjustIng the current in said first series circuit in response to deviations thereof to maintain predetermined current relationships with the current in said second series circuit.
Claim 3
Dependent Claim
114 words
A current amplifier as claimed in claim 1 further comprising a resistor coupling the collector of said second transistor to said second terminal of said power supply input means, and a fourth transistor of the type having a larger base to emitter amplification factor than that of said second transistor for cooperating with said second transistor to increase the output current of said current amplifier, the collector of said fourth transistor being connected to the emitter of said second transistor, the base of said fourth transistor being connected to the collector of said second transistor, and the emitter of said fourth transistor being connected to said second terminal of said power supply input means.
Claim 4
Dependent Claim
30 words
A current amplifier as claimed in claim 1 wherein resistors are arranged between the collectors of the first and second transistors and the terminals of said power supply input means.
Claim 5
Dependent Claim
33 words
A current amplifier as claimed in claim 3 wherein said resistors are each shunted by the base emitter path of a transistor having its collector connected to the emitter of said first transistor.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |