US3786338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transformer for direct and/or alternating currents
Assignee: Technical Management Services
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Filing: 1971-09-27
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Granted: 1974-01-15
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Expires: 1991-09-27
Abstract
Abstract The transformer device has drive and sense windings, a high-gain differential amplifier for supplying magnetization current and negative feedback from the sense winding to the amplifier. A switching circuit is provided for repeatedly reversing the connections of the input terminals to the primary winding, and circuitry is provided for causing the magnetic flux in the core of the transformer to excursion symmetrically below saturation level, thus enabling operation with D.C. input signals. Specifically, a storage capacitor is charged during one sub-cycle of the switching, and then is connected in series with the input during the next sub-cycle to restore the core magnetization and ensure that the transformer will not saturate. A transformer operable by either A.C. or D.C. is formed by oppositely operating two transformers in which the inputs are reversed and flux levels are controlled to prevent saturation. A transformer with a coaxial winding terminated at each end with its characteristic impedance also is provided. Such termination provides critical damping of voltage transients.
Inventors
- 👤 R Gilbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:03
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/34; H03M1/38; H03M1/42; H03M1/66; H03M1/72
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
109 words
A voltage conversion device having a magnetic core, first and second primary windings and a secondary winding on said core, said first primary winding comprising the conductor in a co-axial cable, and said second primary winding comprising the shield surrounding said conductor in said cable, means for terminating said cable at each end with its characteristic impedance, amplifier means for supplying drive current to one of said primary windings, the other of said primary windings being connected to the input of said amplifier means and to an electrical source, said shield and said conductor providing means for feeding said drive current back to the input of said amplifier means.
Claim 2
Dependent Claim
109 words
A voltage conversion device having a magnetic core, first and second primary windings and a secondary winding on said core, said first primary winding comprising the conductor in a co-axial cable, and said second primary winding comprising the shield surrounding said conductor in said cable, means for terminating said cable at each end with its characteristic impedance, amplifier means for supplying drive current to one of said primary windings, the other of said primary windings being connected to the input of said amplifier means and to an electrical source, said shield and said conductor providing means for feeding said drive current back to the input of said amplifier means.
Claim 3
Dependent Claim
20 words
A device as in claim 1 including means connected between said primary windings for electrically isolating them from one another.
Claim 4
Dependent Claim
30 words
A transformer as in claim 2 in which said isolating means includes a series L-C circuit whose resonant frequency is substantially the same as the resonant frequency of said cable.
Claim 5
Dependent Claim
92 words
A transformer having a magnetic core, a co-axial cable having an external shielding conductor and at least one internal conductor, said cable being wound on said core to form windings of said transformer, impedances connected at each end of said cable, said impedances being matched to the characteristic impedance of said cable, and means at at least one end of said cable for electrically isolating said conductors from one another at operating frequencies, but providing a substantially short-circuit connection of the impedance between said conductors at the resonant frequency of said cable.
Claim 6
Dependent Claim
92 words
A transformer having a magnetic core, a co-axial cable having an external shielding conductor and at least one internal conductor, said cable being wound on said core to form windings of said transformer, impedances connected at each end of said cable, said impedances being matched to the characteristic impedance of said cable, and means at at least one end of said cable for electrically isolating said conductors from one another at operating frequencies, but providing a substantially short-circuit connection of the impedance between said conductors at the resonant frequency of said cable.
Claim 7
Dependent Claim
31 words
A transformer as in claim 4 in which said internal conductor serves as the primary winding of said transformer, and said shielding conductor serves as a secondary winding of said transformer.
Claim 8
Dependent Claim
50 words
A transformer as in claim 4 in which one of said windings is a sense winding and the other is a drive winding, a high-gain electronic amplifier whose output is connected to said drive winding, said sense winding being connected in negative feedback relationship to the input of said amplifier.
Claim 9
Dependent Claim
30 words
A transformer as in claim 4 in which said isolating means includes a series L-C circuit whose resonant frequency is substantially the same as the resonant frequency of said cable.
Claim 10
Dependent Claim
57 words
A transFormer as in claim 7 in which said impedances are resistors, each connected at one end to said internal conductor, said L-C circuit being connected between the other end of one of said resistors and said shielding conductor, and a high-gain amplifier connected to said other end of said one resistor and to said shielding conductor.
Claim 11
Dependent Claim
116 words
A transformer operable by D.C. signals, said transformer comprising a core, a primary drive winding on said core, a secondary winding on said core, and a sense winding on said core, a high-gain electronic amplifier, a pair of input terminals, means for connecting the output of said amplifier to said drive winding, means connecting said sense winding to said amplifier to provide negative feedback for said amplifier, switching means for cyclically connecting said input terminals to said amplifier with reversed polarity, and means for storing a signal proportional to the magnetization current of said transformer during one sub-cycle of its operation, and then adding said signal to the input signal during the next sub-cycle of operation.
Claim 12
Dependent Claim
116 words
A transformer operable by D.C. signals, said transformer comprising a core, a primary drive winding on said core, a secondary winding on said core, and a sense winding on said core, a high-gain electronic amplifier, a pair of input terminals, means for connecting the output of said amplifier to said drive winding, means connecting said sense winding to said amplifier to provide negative feedback for said amplifier, switching means for cyclically connecting said input terminals to said amplifier with reversed polarity, and means for storing a signal proportional to the magnetization current of said transformer during one sub-cycle of its operation, and then adding said signal to the input signal during the next sub-cycle of operation.
Claim 13
Dependent Claim
44 words
A transformer as in claim 9 in which said switching means includes a plurality of pairs of FETs, means for switching the FETs of one pair off and the FETs of the other pair on and then reversing the conditions of the FET pairs.
Claim 14
Dependent Claim
91 words
A transformer for D.C., said transformer comprising a core, primary drive, secondary and sense windings on said core, a high-gain electronic amplifier, a pair of input terminals, means for supplying a negative feedback signal from said sense winding to said amplifier, switching means for cyclically connecting said input terminals to said amplifier with first one and then the opposite polarity, and for periodically connecting said amplifier with said drive winding to supply magnetization current to said drive winding, and means for maintaining said magnetizing current below saturation level for said core.
Claim 15
Dependent Claim
91 words
A transformer for D.C., said transformer comprising a core, primary drive, secondary and sense windings on said core, a high-gain electronic amplifier, a pair of input terminals, means for supplying a negative feedback signal from said sense winding to said amplifier, switching means for cyclically connecting said input terminals to said amplifier with first one and then the opposite polarity, and for periodically connecting said amplifier with said drive winding to supply magnetization current to said drive winding, and means for maintaining said magnetizing current below saturation level for said core.
Claim 16
Dependent Claim
37 words
A device as in claim 11 in which the maintaining means comprises means for storing a charge proportional to the magnetizing current during one sub-cycle, and using said charge during the next sub-cycle to drive said amplifier.
Claim 17
Dependent Claim
15 words
A device as in claim 12 in which said amplifier is a high-gain differential amplifier.
Claim 18
Dependent Claim
133 words
A device as in claim 13 in which the output of said differential amplifier is connected to one terminal called the ''''high'''' terminal of said drive winding, said sense winding having its ''''high'''' terminal (the terminal whose voltage tracks with the voltage at the ''''high'''' terminal of the drive winding) connected to the inverting input lead of said differential amplifier, the other terminal (called the ''''low'''' terminal) of said drive winding being connected to one terminal of a storage capacitor, cyclical electronic switching means for connecting one of said input terminals to the non-inverting input of said amplifier and connecting said capacitor in series with said input terminal during a first sub-cycle, and for reversing the connection of said input terminals and disconnecting said capacitor from the amplifier input during the next sub-cycle.
Claim 19
Dependent Claim
42 words
A device as in claim 11 in which each cycle of operation of said switching means is divided into a flux-linked sub-cycle and a restore sub-cycle, and sampling means for sampling the voltage on said secondary winding only during said flux-linked sub-cycle.
Claim 20
Dependent Claim
30 words
A device as in claim 15 in which said sampling means is operative only during a selected portion of said flux-linked sub-cycle, substantially later than the initiation of said sub-cycle.
Claim 21
Dependent Claim
94 words
A device as in claim 11 including a plurality of secondary windings on said core, said secondary windings having numbers of turns varying in accordance with a code, a second core, two coupling windings, one on each core, connected together in series with one another, the number of turns on the coupling winding of the second core being a multiple of the number of turns of the coupling winding on the first-named core, a pluRality of secondary windings on said second core, the latter secondary windings representing the least significant bits in said core.
Claim 22
Dependent Claim
67 words
A device as in claim 17 including a second drive winding wound on the second core and connected in series with the first-named drive winding, the ratio of the number of turns on said first drive winding to the number of turns on said second drive winding being the inverse of the ratio of turns of said first coupling winding to that of said second coupling winding.
Claim 23
Dependent Claim
116 words
An A.C.-D.C. transformer comprising a pair of input terminals, a first core having a first primary winding and a first secondary winding, a second core having a second primary winding and a second secondary winding, switching means for alternatingly connecting said input terminals to said primary windings, first to said first primary winding in one sense and to said second primary winding in the opposite sense, and then to said first primary winding in said opposite sense and to said second primary winding in said one sense, means for operating said switching means repeatedly, and flux-limiting means for maintaining the magnetic flux in each core at a level below that which causes saturation of said core.
Claim 24
Dependent Claim
116 words
An A.C.-D.C. transformer comprising a pair of input terminals, a first core having a first primary winding and a first secondary winding, a second core having a second primary winding and a second secondary winding, switching means for alternatingly connecting said input terminals to said primary windings, first to said first primary winding in one sense and to said second primary winding in the opposite sense, and then to said first primary winding in said opposite sense and to said second primary winding in said one sense, means for operating said switching means repeatedly, and flux-limiting means for maintaining the magnetic flux in each core at a level below that which causes saturation of said core.
Claim 25
Dependent Claim
38 words
A device as in claim 19 including output terminals and further switching means operating in synchronism with the first-named switching means for connecting said output terminals first to one and then to the other of said secondary windings.
Claim 26
Dependent Claim
46 words
A device as in claim 20 in which each cycle of operation of said switching means is divided into a flux-linked sub-cycle and a restore sub-cycle, said further switching means including sampling means for sampling the voltage on said secondary winding only during said flux-linked sub-cycle.
Claim 27
Dependent Claim
30 words
A device as in claim 21 in which said sampling means is operative only during a selected portion of said flux-linked sub-cycle, substantially later than the initiation of said sub-cycle.
Claim 28
Dependent Claim
55 words
A device as in claim 19 including a high-gain amplifier connected to each of said primary windings to supply magnetizing current thereto, a sense winding on each core, means for negatively feeding back to said amplifier the signal on said sense winding, and means for maintaining the magnetizing current below saturation level in each core.
Claim 29
Dependent Claim
54 words
A device as in claim 19 in which each cycle of operation of said switching means is divided into a flux-linked sub-cycle and a restore sub-cycle, in which said switching means includes means for causing a substantial amount of time overlap of the flux-linked sub-cycles of the primary windings on the two different cores.
Claim 30
Dependent Claim
61 words
A device as in claim 19 in which each cycle of operation of said switching means is divided into a flux-linked sub-cycle and a restore sub-cycle, and sampling means for sampling the voltage on said secondary winding only during said flux-linked sub-cycle, including means for making the flux-linked sub-cycle for each core of substantially longer time duration than the restore sub-cycle.
Claim 31
Dependent Claim
128 words
A transformer having a magnetic core, a co-axial cable having an external shielding conductor and at least one internal conductor, said cable being wound on said core to form drive and sense windings of said transformer, a high-gain electronic amplifier whose output is connected to said drive winding, said sense winding being connected in negative feedback relationship to the input of said amplifier, a pair of input terminals, switching means for cyclically connecting said input terminals to said amplifier with reversing polarity, and for connecting storage means to store a signal which represents the magnetization current during one sub-cycle of operation, and connecting that signal to the input of said amplifier during the next sub-cycle, and means for terminating said cable at each end with its characteristic impedance.
Claim 32
Dependent Claim
128 words
A transformer having a magnetic core, a co-axial cable having an external shielding conductor and at least one internal conductor, said cable being wound on said core to form drive and sense windings of said transformer, a high-gain electronic amplifier whose output is connected to said drive winding, said sense winding being connected in negative feedback relationship to the input of said amplifier, a pair of input terminals, switching means for cyclically connecting said input terminals to said amplifier with reversing polarity, and for connecting storage means to store a signal which represents the magnetization current during one sub-cycle of operation, and connecting that signal to the input of said amplifier during the next sub-cycle, and means for terminating said cable at each end with its characteristic impedance.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |