Patent US6169484B1 successfully refreshed from Google Patents.
US4403198A
Expired / Lapsed
US
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Biasing circuit for MOSFET power amplifiers
Assignee: General Electric Co
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Filing: 1981-03-27
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Granted: 1983-09-06
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Expires: 2001-03-27
Abstract
Abstract A biasing circuit for MOSFET power amplifiers in complementary pair push-pull single ended or bridge configuration. The biasing circuit includes a complementary pair of bi-polar transistors operating as common base amplifiers. Each amplifier includes emitter and collector resistances. A portion of the collector resistance of each common base amplifier acts as a gate-source biasing resistor for an associated MOSFET power transistor. The active feedback circuit is responsive to the voltage at a center tap of the primary winding of the amplifiers output transformer. The effect of the active feedback arrangement is to reduce the closed loop voltage gain of a conventional bridge amplifier from approximately 8.5 to approximately 0.9 thereby minimizing voltage fluctuations at the center tap of the primary of the output transformer.
Inventors
- 👤 Otward Muller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:37
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/30; H03F1/307; H03F1/308; H03F3/00; H03F3/30; H03F3/3001; H03F3/3061
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
77 words
An amplifier circuit comprising: a complementary pair of MOSFET amplifier elements arranged in push-pull configuration; an output transformer having a center-tapped primary winding coupled to said MOSFET elements and a secondary winding for driving a load coupled thereto; and an active feedback circuit, respponsive to a signal at the center tap of said primary winding, for controlling DC bias levels of said MOSFET amplifier elements, thereby preventing substantial fluctuation of the signal level at the center tap.
Claim 2
Dependent Claim
77 words
An amplifier circuit comprising: a complementary pair of MOSFET amplifier elements arranged in push-pull configuration; an output transformer having a center-tapped primary winding coupled to said MOSFET elements and a secondary winding for driving a load coupled thereto; and an active feedback circuit, respponsive to a signal at the center tap of said primary winding, for controlling DC bias levels of said MOSFET amplifier elements, thereby preventing substantial fluctuation of the signal level at the center tap.
Claim 3
Dependent Claim
25 words
An amplifier according to claim 1 wherein said active feedback circuit comprises a bi-polar transistor pair arranged so as to provide two common-base amplifier stages.
Claim 4
Dependent Claim
35 words
An amplifier according to claim 2 wherein said common-base amplifier stages each include collector resistors and wherein a portion of such a collector resistor acts as a biasing resistor for a corresponding MOSFET amplifier element.
Claim 5
Dependent Claim
39 words
An amplifier according to claim 3 wherein said MOSFET amplifier elements are arranged in a common source configuration and wherein said portion of such a collector resistor acts as a gate-source biasing resistor for a corresponding MOSFET amplifier element.
Claim 6
Dependent Claim
20 words
An amplifier according to claim 2, 3, or 4 wherein the voltage gain of each common-base amplifier is substantially unity.
Claim 7
Dependent Claim
83 words
An amplifier circuit comprising: a complementary pair push-pull bridge configuration of power amplifier elements including at least four (4) amplifier elements; an output transformer having a center-tapped primary winding coupled to said amplifier elements and a secondary winding for driving a load coupled thereto; and an active feedback circuit, responsive to a signal at the center tap of said primary winding, for controlling the DC bias levels of said amplifier elements, thereby preventing substantial fluctuation of the signal level at the center tap.
Claim 8
Dependent Claim
83 words
An amplifier circuit comprising: a complementary pair push-pull bridge configuration of power amplifier elements including at least four (4) amplifier elements; an output transformer having a center-tapped primary winding coupled to said amplifier elements and a secondary winding for driving a load coupled thereto; and an active feedback circuit, responsive to a signal at the center tap of said primary winding, for controlling the DC bias levels of said amplifier elements, thereby preventing substantial fluctuation of the signal level at the center tap.
Claim 9
Dependent Claim
20 words
An amplifier according to claim 6 wherein said amplifier elements comprise MOSFET power transistors arranged in a common source configuration.
Claim 10
Dependent Claim
25 words
An amplifier according to claim 6 wherein said active feedback circuit comprises a bi-polar transistor pair arranged so as to provide two common-base amplifier stages.
Claim 11
Dependent Claim
33 words
An amplifier according to claim 8 wherein said common-base amplifier stages each include collector resistors and wherein a portion of such a collector resistor acts as a biasing resistor for corresponding amplifier element.
Claim 12
Dependent Claim
41 words
An amplifier according to claim 9 wherein said amplifier elements are MOSFET power transistors arranged in a common source configuration and wherein said portion of such a collector resistor acts as a gate-source biasing resistor for a corresponding MOSFET power transistor.
Claim 13
Dependent Claim
25 words
An amplifier according to claim 8, 9, or 10 wherein the voltage gain of each common-base amplifier is substantially unity or of any suitable value.
Claim 14
Dependent Claim
81 words
An amplifier comprising: four (4) amplifier elements arranged in a complementary pair push-pull bridge configuration; an output transformer having a center-tapped primary winding, one side of said primary winding being coupled to each complementary pair and a secondary winding adapted to be coupled to a load; and an active feedback circuit, responsive to a signal at said center tap, for controlling the DC bias levels of the amplifier elements so as to maintain a bridge that is substantially in DC balance.
Claim 15
Dependent Claim
81 words
An amplifier comprising: four (4) amplifier elements arranged in a complementary pair push-pull bridge configuration; an output transformer having a center-tapped primary winding, one side of said primary winding being coupled to each complementary pair and a secondary winding adapted to be coupled to a load; and an active feedback circuit, responsive to a signal at said center tap, for controlling the DC bias levels of the amplifier elements so as to maintain a bridge that is substantially in DC balance.
Claim 16
Dependent Claim
20 words
An amplifier according to claim 12 wherein said amplifier elements comprise MOSFET power transistors arranged in a common source configuration.
Claim 17
Dependent Claim
25 words
An amplifier according to claim 12 wherein said active feedback circuit comprises a bi-polar transistor pair arranged so as to provide two common-base amplifier stages.
Claim 18
Dependent Claim
33 words
An amplifier according to claim 14 wherein said common-base amplifier stages each include collector resistors and wherein a portion of such a collector resistor acts as a biasing resistor for corresponding amplifier element.
Claim 19
Dependent Claim
41 words
An amplifier according to claim 15 wherein said amplifier elements are MOSFET power transistors arranged in a common source configuration and wherein said portion of such a collector resistor acts as a gate-source biasing resistor for a corresponding MOSFET power transistor.
Claim 20
Dependent Claim
26 words
An amplifier according to claim 14, 15, or 16 wherein the voltage gain of each common-base amplifier is substantially unity or of any other suitable value.
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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) | 1986-09-05 | 1987-03-07 | 1987-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-05 | 1991-03-07 | 1991-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-05 | 1995-03-07 | 1995-09-06 | $7700.00 | Window Closed / Lapsed |