US3881149A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compensated transformer circuit
Assignee: Lorain Products Corp
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Filing: 1973-08-23
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Granted: 1975-04-29
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Expires: 1993-08-23
Abstract
Abstract A circuit for reducing or eliminating the effect of the magnetizing inductance of a transformer on voice-frequency signals coupled through that transformer. Circuitry is provided to generate voltages and currents which simulate the presence of a negative inductance and to couple those voltages and currents to a transformer in cancelling relationship to the magnetizing inductance thereof. Circuitry is also provided to reduce or eliminate the effect of the equivalent shunt resistance of the transformer and thereby render the transformer virtually free of core losses. Finally, circuitry is provided to linearize the nonlinear magnetization characteristics of non-linear cores and thereby substantially reduce the distortion of signals coupled through the transformer.
Inventors
- 👤 Frederick J Kiko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:30
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/42; H01F19/00; H01F19/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
121 words
A transformer circuit which provides an uninterrupted path for the flow of primary and secondary current and which compensates for the frequency dependent attenuation of transformer signals that is introduced by the magnetizing inductance of the transformer comprising, in combination, a magnetic core, primary, secondary and tertiary windings disposed on said core, an impedance simulating network including feedback circuitry for establishing voltages and currents which affect the circuitry to which said voltages and currents are applied as if a negative inductance were connected to said circuitry, said negative inductance having a magnitude proportional to the magnetizing inductance of said transformer, and means for connecting said impedance simulating network to said tertiary winding to effectively cancel the magnetizing inductance of said transformer.
Claim 2
Dependent Claim
121 words
A transformer circuit which provides an uninterrupted path for the flow of primary and secondary current and which compensates for the frequency dependent attenuation of transformer signals that is introduced by the magnetizing inductance of the transformer comprising, in combination, a magnetic core, primary, secondary and tertiary windings disposed on said core, an impedance simulating network including feedback circuitry for establishing voltages and currents which affect the circuitry to which said voltages and currents are applied as if a negative inductance were connected to said circuitry, said negative inductance having a magnitude proportional to the magnetizing inductance of said transformer, and means for connecting said impedance simulating network to said tertiary winding to effectively cancel the magnetizing inductance of said transformer.
Claim 3
Dependent Claim
41 words
A transformer circuit as set forth in claim 1 wherein the impedance simulating network includes means for establishing, in parallel with said negative inductance, a negative resistance having a magnitude that is proportional to the equivalent shunt resistance of said transformer.
Claim 4
Dependent Claim
40 words
A transformer circuit as set forth in claim 1 wherein the impedancE simulating network includes means for establishing, in series with said negative inductance, a negative resistance having a magnitude substantially equal to the series resistance of said tertiary winding.
Claim 5
Dependent Claim
42 words
A transformer circuit as set forth in claim 3 wherein the impedance simulating network includes means for establishing, in parallel with said negative inductance, a negative resistance having a magnitude that is substantially proportional to the equivalent shunt resistance of said transformer.
Claim 6
Dependent Claim
43 words
A transformer circuit as set forth in claim 1 wherein said magnetic core has a non-linear magnetizing characteristic which causes the magnetizing inductance of the transformer to be non-linear, and wherein said impedance simulating network establishes a negative inductance which is similarly non-linear.
Claim 7
Dependent Claim
53 words
A transformer circuit as set forth in claim 5 wherein said impedance simulating network includes a second magnetic core made up of the same material as the magnetic core of said transformer, said second core being arranged to operate about the same flux density operating point as the magnetic core of said transformer.
Claim 8
Dependent Claim
40 words
A transformer circuit as set forth in claim 5 wherein the impedance simulating network includes means for establishing, in series with said negative inductance, a negative resistance having a magnitude substantially equal to the series resistance of said tertiary winding.
Claim 9
Dependent Claim
42 words
A transformer circuit as set forth in claim 7 wherein the impedance simulating network includes means for establishing, in parallel with said negative inductance, a negative resistance having a magnitude that is substantially proportional to the equivalent shunt resistance of said transformer.
Claim 10
Dependent Claim
73 words
A transformer circuit as set forth in claim 1 wherein said impedance simulating network includes: an operational amplifier having an inverting input, a non-inverting input and an output, a positive feedback impedance connected between the output and non-inverting input of said amplifier, a negative feedback impedance connected between the output and inverting input of said amplifier, an input feedback impedance connected between said tertiary winding and one of the inputs of said amplifier.
Claim 11
Dependent Claim
18 words
A transformer circuit as set forth in claim 9 in which said negative feedback means includes a capacitor.
Claim 12
Dependent Claim
17 words
A transformer circuit as set forth in claim 10 including a resistor in parallel with said capacitor.
Claim 13
Dependent Claim
17 words
A transformer circuit as set forth in claim 10 including a resistor is series with said capacitor.
Claim 14
Dependent Claim
27 words
A transformer circuit as set forth in claim 10 including a first resistor in parallel with said capacitor and a second resistor in series with said capacitor.
Claim 15
Dependent Claim
40 words
A transformer circuit as set forth in claim 9 in which said input feedback impedance includes a second magnetic core, said second magnetic core being operated about the same flux density operating point as the magnetic core of said transformer.
Claim 16
Dependent Claim
19 words
A transformer circuit as set forth in claim 14 in which said positive and negative feedback impedances comprise resistors.
References Cited (Backward Citations)
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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) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |