US3652948A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power amplifier including plurality of push-pull amplifier sections coupled by ferrite matching transformers
Assignee: Motorola Solutions Inc
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Filing: 1970-02-24
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Granted: 1972-03-28
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Expires: 1990-02-24
Abstract
Abstract A high power semiconductor amplifier, which may be used as the power amplifier of a radio transmitter, includes a plurality of push-pull amplifier sections cooperating to provide the required output power. The amplifier sections are coupled by broadband transformers having ferrite cores and a plurality of inter-wound coils. This provides direct current isolation of the sections and a high degree of coupling as required for broadband operation, and also results in stable operation and signals in the two amplifier sections which are in close phase relationship so that the outputs thereof can be combined in-phase for maximum efficiency. The coupling circuit at the input and/or the output of the sections includes windings of the transformers in series with a variable reactance element for tuning the same. The amplifier is usable over a wide range of frequencies with a minimum of adjustment.
Inventors
- 👤 Gary N Fierstien
- 👤 Paul A Talvensaari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:00
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/26; H03F3/20; H03F3/24; H03F3/245
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
169 words
A power amplifier circuit for operation at a frequency in the range above 25 megahertz including in combination, a plurality of amplifier sections each including a pair of transistors connected in push-pull and having an input circuit and an output circuit, a plurality of wide band transformers each having a ferriTe core and first and second closely coupled winding means on said core, one of said input circuits and said output circuits of said amplifier sections including respectively said first winding means of said transformers, a first circuit including said second winding means of all of said transformers and variable reactance means for tuning the same, with said second winding means of all of said transformers and said variable reactance means being connected in series with each other, and a second circuit transformer coupled to the other of said input and output Circuits of all of said amplifier sections, said first and second circuits providing direct current isolation of said amplifier sections and holding the signals therein substantially in-phase.
Claim 2
Dependent Claim
169 words
A power amplifier circuit for operation at a frequency in the range above 25 megahertz including in combination, a plurality of amplifier sections each including a pair of transistors connected in push-pull and having an input circuit and an output circuit, a plurality of wide band transformers each having a ferriTe core and first and second closely coupled winding means on said core, one of said input circuits and said output circuits of said amplifier sections including respectively said first winding means of said transformers, a first circuit including said second winding means of all of said transformers and variable reactance means for tuning the same, with said second winding means of all of said transformers and said variable reactance means being connected in series with each other, and a second circuit transformer coupled to the other of said input and output Circuits of all of said amplifier sections, said first and second circuits providing direct current isolation of said amplifier sections and holding the signals therein substantially in-phase.
Claim 3
Dependent Claim
50 words
A power amplifier circuit in accordance with claim 1 wherein each of said amplifier sections includes conductors connecting said transistors to said winding means of said transformers and capacitors connected to said conductors and cooperating with the inductance thereof to form impedance matching sections for efficient stable wide band operation.
Claim 4
Dependent Claim
48 words
A power amplifier circuit in accordance with claim 1 wherein the amplifier is adapted for operation throughout a wide frequency range, and said variable reactance means is the only element of the amplifier circuit which must be adjusted for operation at different frequencies in the wide frequency range.
Claim 5
Dependent Claim
56 words
A power amplifier circuit in accordance with claim 1 wherein said transformers each include an elongated rod core and a pair of primary windings connected in parallel and a pair of secondary windings connected in parallel on said elongate ferrite core, with each of said primary windings being closely coupled to both of said secondary windings.
Claim 6
Dependent Claim
49 words
A power amplifier circuit in accordance with claim 1 wherein said transformers have primary and secondary windings, with said secondary windings connected in said input circuits of said amplifier sections, and said first circuit includes said primary windings of said transformers connected in series with a variable tuning capacitor.
Claim 7
Dependent Claim
72 words
A power amplifier circuit in accordance with claim 5 including first and second amplifier sections each having circuit means coupled to said transformers thereof providing stable wide band operation, and wherein each of said transformers includes an elongated ferrite core having a pair of parallel connected primary windings and a pair of parallel connected secondary windings thereon, with each of said primary windings being closely coupled to both of said secondary windings.
Claim 8
Dependent Claim
23 words
A power amplifier circuit in accordance with claim 5 further including a driver amplifier coupled to said first circuit for applying signals thereto.
Claim 9
Dependent Claim
96 words
A power amplifier circuit in accordance with claim 7 wherein said driver amplifier is a push-pull transistor amplifier, and further including a single ended pre-driver transistor amplifier coupled to said driver amplifier by a coupling circuit including a further transformer having a ferrite core and closely coupled windings thereon, with said coupling circuit further including a variable tuning capacitor which together with the variable tuning capacitor connected in series with said primary windings constitute the only elements of the power amplifier circuit which must be adjusted for operation at different frequencies in a wide frequency range.
Claim 10
Dependent Claim
51 words
A power amplifier circuit in accordance with claim 1 wherein said transformers have primary windings and secondary windings, with said primary windings being connected in said output circuits of said amplifier sections, and said first circuit includes said secondary windings of said transformer connected in series with a variable tuning capacitor.
Claim 11
Dependent Claim
70 words
A power amplifier circuit in accordance with claim 9 including first and second amplifier sections each having circuit means coupled to said transformers thereof providing stable wide band operation, and wherein each of said transformers includes an elonGated ferrite rod core having a pair of parallel connected primary windings and a secondary winding thereon, with each of said primary windings being closely coupled to a portion of said secondary winding.
Claim 12
Dependent Claim
40 words
A power amplifier circuit in accordance with claim 10 wherein said second circuit includes broadband ferrite core transformers coupled to said input circuits of all of said amplifier sections, and further including a driver amplifier coupled to said second circuit.
Claim 13
Dependent Claim
62 words
A power amplifier circuit in accordance with claim 11 including a coupling circuit connected between said driver amplifier and said second circuit having a variable capacitor, with said variable capacitor and said variable reactance means of said first circuit forming the only elements of said power amplifier circuit which must be adjusted for operation at different frequencies in a wide frequency range.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |