Patent US4021751A successfully refreshed from Google Patents.
US4021751A
Expired / Lapsed
US
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Field effect transistor amplifier
Assignee: Sony Corp
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Filing: 1975-11-03
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Granted: 1977-05-03
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Expires: 1995-11-03
Abstract
Abstract A field effect transistor amplifier has a signal input circuit which preferably includes an A-class amplifier, a driving stage having first and second FETs driven in the same phase relation by an input signal applied to their gate electrodes from the signal input circuit, a first voltage source connected to the source electrodes of the first and second FETs, a resistor connected between the drain electrodes of the first and second FETs, an output stage having third and fourth FETs with the gate electrodes of the latter being connected to opposite ends of the resistor so that the voltage across the latter is applied as the DC bias voltage for the FETs of the output stage, a second voltage source connected to the drain electrodes of the third and fourth FETs, and an output terminal connected to the source electrodes of the third and fourth electrodes which are connected to each other. At least the FETs of the output stage are triode characteristic FETs and, if the gain of the A-class amplifier in the signal input circuit is insufficient, the FETs of the driving stage are also triode characteristic FETs.
Inventors
- 👤 Tadao Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:50
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/45376; H03F3/45408; H03F3/181; H03F3/183; H03F3/185; H03F3/1855; H03F3/26; H03F3/30; H03F3/3001; H03F3/3044; H03F3/45466; H10; H10D; H10D99/00; H03F2200/00; H03F2200/516; H03F2203/00; H03F2203/45; H03F2203/45498; H03F2203/45702
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
188 words
A field effect transistor amplifier comprising first DC voltage source means, first and second field effect transistors each having gate, source and drain electrodes, a resistor connected between the drain electrodes of said first and second field effect transistors, means connecting the source electrodes of said first and second field effect transistors to said first DC voltage source means, input circuit means for applying to the gate electrodes of said first and second field effect transistors respective signals of the same polarity corresponding to an input signal to be amplified, second DC voltage source means, third and fourth field effect transistors each having gate, source and drain electrodes, the drain electrodes of said third and fourth field effect transistors being connected to said second DC voltage source means, the source electrodes of said third and fourth field effect transistors being connected to each other, an output terminal connected to the connected together source electrodes of said third and fourth field effect transistors, and means for applying the voltage across said resistor as a DC bias voltage to the gate electrodes of said third and fourth field effect transistors.
Claim 2
Dependent Claim
188 words
A field effect transistor amplifier comprising first DC voltage source means, first and second field effect transistors each having gate, source and drain electrodes, a resistor connected between the drain electrodes of said first and second field effect transistors, means connecting the source electrodes of said first and second field effect transistors to said first DC voltage source means, input circuit means for applying to the gate electrodes of said first and second field effect transistors respective signals of the same polarity corresponding to an input signal to be amplified, second DC voltage source means, third and fourth field effect transistors each having gate, source and drain electrodes, the drain electrodes of said third and fourth field effect transistors being connected to said second DC voltage source means, the source electrodes of said third and fourth field effect transistors being connected to each other, an output terminal connected to the connected together source electrodes of said third and fourth field effect transistors, and means for applying the voltage across said resistor as a DC bias voltage to the gate electrodes of said third and fourth field effect transistors.
Claim 3
Dependent Claim
29 words
A field effect transistor amplifier according to claim 1; in which at least each of said third and fourth field effect transistors is a triode characteristic field effect transistor.
Claim 4
Dependent Claim
29 words
A field effect transistor amplifier according to claim 1; in which each of said first, second, third and fourth field effect transistors is a triode characteristic field effect transistor.
Claim 5
Dependent Claim
32 words
A field effect transistor amplifier according to claim 1; in which said first and second field effect transistors have complementary characteristics, and said third and fourth field effect transistors have complementary characteristics.
Claim 6
Dependent Claim
83 words
A field effect transistor amplifier according to claim 1; further comprising first and second voltage injecting means connecting said second DC voltage source means to said source electrodes of said first and second field effect transistors for applying a ripple voltage in said second DC voltage source means to said source electrode of said first and second field effect transistors, respectively, so that said voltage across said resistor is stabilized in respect to voltage fluctuations occurring in said second DC voltage source means.
Claim 7
Dependent Claim
78 words
A field effect transistor amplifier according to claim 5; in which said means connecting said source electrodes of said first and second field effect transistors to said first DC voltage source means are constituted by second and third resistors, respectively, and said first and second voltage injecting means respectively include a fourth resistor and a fifth resistor connected between said second DC voltage source means and said source electrodes of said first and second field effect transistors, respectively.
Claim 8
Dependent Claim
61 words
A field effect transistor amplifier according to claim 6; in which the first mentioned resistor and said fourth and fifth resistors have resistance values R 1 , R 4 and R 5 , respectively, which satisfy the following equations: ##EQU16## in which μ 3 and μ 4 are the voltage amplification factors of said third and fourth field effect transistors, respectively.
Claim 9
Dependent Claim
83 words
A field effect transistor amplifier according to claim 6; in which said resistance values of said fourth and fifth resistors further satisfy the following equations: ##EQU17## in which I is the current flowing through said first resistor and said first and second field effect transistors for the pinch-off voltages of said third and fourth field effect transistors, and k is a constant for said third and fourth field effect transistors determined by the product of the respective pinch-off voltage and voltage amplification factor.
Claim 10
Dependent Claim
50 words
A field effect transistor amplifier according to claim 1; in which each of said first, second, third and fourth field effect transistors is a triode characteristic field effect transistor; and in which said input circuit means includes an A-class amplifying stage for driving said first and second field effect transistors.
Claim 11
Dependent Claim
53 words
A field effect transistor amplifier according to claim 9; in which said A-class amplifying stage of the input circuit means includes fifth and sixth field effect transistors connected in complementary push-pull relationship to said first DC voltage source means for driving said first and second field effect transistors with the same phase relationship.
Claim 12
Dependent Claim
39 words
A field effect transistor amplifier according to claim 10; further comprising negative voltage feedback means between said connected together source electrodes of said third and fourth field effect transistors and said A-class amplifying stage of the input circuit means.
Claim 13
Dependent Claim
26 words
A field effect transistor amplifier according to claim 9; in which said A-class amplifying stage of the input circuit means includes a pair of differential amplifiers.
Claim 14
Dependent Claim
25 words
A field effect transistor amplifier according to claim 9; in which said input circuit means further includes a differential amplifier preceding said A-class amplifying stage.
References Cited (Backward Citations)
US3921089A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |