Patent US5045803A successfully refreshed from Google Patents.
US5045803A
Expired / Lapsed
US
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Amplification circuit with a determined input impedance and various transconductance values
Assignee: POSITRON Corp A TEXAS CORP
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Filing: 1990-08-15
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Granted: 1991-09-03
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Expires: 2010-08-15
Abstract
Abstract A voltage-current amplification circuit comprises two sub-circuits (B1, B2), each of which comprises a differential amplifier (D), a resistor (R4), a transistor (T), and a first switch (K1) connected between the transistor base and ground. Each sub-circuit (B1, B2) also comprises an additional amplifier (A1, A2), and an additional resistor (R2a, R2b), respectively. The inputs of the additional amplifiers being connected to ground through a common resistor (R) and to the emitters of the two transistors through a common resistor (R1). Each sub-circuit further comprises a second switch (K2) formed by a single transistor.
Inventors
- 👤 Philippe Perroud
- 👤 Jean-Luc Jaffard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:36
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/68; H03F3/72
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
239 words
A voltage-current amplification circuit connected between an input terminal and first or second output terminals, said circuit comprising first and second sub-circuits, each sub-circuit comprising: (a) a first differential amplifier, a first input of which is connected to the input terminal through a first resistor, (b) a transistor, the having a base connected to the output of the differential amplifier and having an emitter and a collector, and, (c) a first switch connected between the transistor base and ground, the first sub-circuit comprising a second amplifier, the output of which is connected to a second input of the differential amplifier, and a second resistor connected between the transistor emitter and the first input of the differential amplifier, the second sub-circuit comprising a third amplifier, the output of which is connected to the second input of the differential amplifier, and a third resistor connected between the transistor emitter and the first input of the differential amplifier, the transistor collectors of the first and second sub-circuits being connected to the first and second output terminals, respectively, and the inputs of the second and third amplifiers being connected to ground through a common fourth resistor and to the emitters of the two transistors through a common fifth resistor, wherein each said first and second sub-circuits further comprises a second switch connected between the first input of the differential amplifier and ground, each of said second switches being formed by a single transistor.
Claim 2
Dependent Claim
239 words
A voltage-current amplification circuit connected between an input terminal and first or second output terminals, said circuit comprising first and second sub-circuits, each sub-circuit comprising: (a) a first differential amplifier, a first input of which is connected to the input terminal through a first resistor, (b) a transistor, the having a base connected to the output of the differential amplifier and having an emitter and a collector, and, (c) a first switch connected between the transistor base and ground, the first sub-circuit comprising a second amplifier, the output of which is connected to a second input of the differential amplifier, and a second resistor connected between the transistor emitter and the first input of the differential amplifier, the second sub-circuit comprising a third amplifier, the output of which is connected to the second input of the differential amplifier, and a third resistor connected between the transistor emitter and the first input of the differential amplifier, the transistor collectors of the first and second sub-circuits being connected to the first and second output terminals, respectively, and the inputs of the second and third amplifiers being connected to ground through a common fourth resistor and to the emitters of the two transistors through a common fifth resistor, wherein each said first and second sub-circuits further comprises a second switch connected between the first input of the differential amplifier and ground, each of said second switches being formed by a single transistor.
Claim 3
Dependent Claim
32 words
An amplification circuit according to claim 1, wherein each said first and second output terminals is connected to a different VTR head adapted respectively to a "normal duration" or "long duration" mode.
Claim 4
Dependent Claim
51 words
An amplication circuit according to claim 1, wherein gains of the second and third amplifiers are equal to R4/(R2a+R4) and R4/(R2b+R4), respectively, where R4 is the resistance value of the first resistor, R2a is the resistance value of the second resistor and R2b is the resistance value of the third resistor.
Claim 5
Dependent Claim
24 words
An amplification circuit according to claim 1, wherein each first switch is formed by a single transistor set to saturation mode when switched on.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-09-02 | 1995-03-04 | 1995-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-02 | 1999-03-04 | 1999-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-02 | 2003-03-04 | 2003-09-03 | $7700.00 | Window Closed / Lapsed |