US3818314A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency controlled inverter
Assignee: AT&T Inc
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Filing: 1973-06-11
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Granted: 1974-06-18
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Expires: 1993-06-11
Abstract
Abstract In a regulated dc to dc converter, a ferroresonant regulator is combined with a push-pull inverter on the same transformer, and a feedback circuit controls the frequency of the inverter in response to the rectified output of the regulator. A control winding on the inverter transformer is tightly coupled to the base drive windings that supply drive to the inverter transistors and loosely coupled to the primary winding that is driven by the transistors. The control winding is short circuited each half cycle at a time determined by the feedback circuit to reflect a low impedance into the base drive windings and a higher inductive impedance into the primary winding. The higher inductive impedance in combination with a capacitor in parallel with the primary winding forms a resonant circuit which insures efficient commutation of the inverter transistors and the control winding short circuiting device.
Inventors
- 👤 G Miller
- 👤 J Bishop
- 👤 R Kakalec
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:44
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/338; H02M3/3385; H02M3/3387; H02M3/3388; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
154 words
An inverter of the type comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a multiplicity of windings including at least a center tapped primary winding interconnecting said transconductive paths and a pair of base drive windings, each of said base drive windings connected in series with a respective one of said biasing paths, and switching means connected to at least one of said multiplicity of windings and effective when operated to complete a current path to initiate reversal of the direction of current in said windings, CHARACTERIZED IN THAT said base drive windings are loosely coupled to said primary winding and operation of said switching means completes a low impedance path across said at least one winding to reduce the effective impedance across said base drive windings to a low value and the effective impedance across said primary winding to a higher inductive value.
Claim 2
Dependent Claim
154 words
An inverter of the type comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a multiplicity of windings including at least a center tapped primary winding interconnecting said transconductive paths and a pair of base drive windings, each of said base drive windings connected in series with a respective one of said biasing paths, and switching means connected to at least one of said multiplicity of windings and effective when operated to complete a current path to initiate reversal of the direction of current in said windings, CHARACTERIZED IN THAT said base drive windings are loosely coupled to said primary winding and operation of said switching means completes a low impedance path across said at least one winding to reduce the effective impedance across said base drive windings to a low value and the effective impedance across said primary winding to a higher inductive value.
Claim 3
Dependent Claim
135 words
An inverter of the type comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a center tapped primary winding interconnecting said transconductive paths, a pair of base drive windings, each of said base drive windings connected in series with a respective one of said biasing paths, and a control winding, and switching means cooperating with said control winding to couple impedances to said primary windings to initiate reversal of current in said transformer windings, CHARACTERIZED IN THAT said control winding is tightly coupled to said base drive windings and loosely coupled to said primary winding, and said switching means operates to substantially short circuit said control winding, thereby reflecting a low impedance into said base drive windings and a higher inductive impedance into said primary winding.
Claim 4
Dependent Claim
135 words
An inverter of the type comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a center tapped primary winding interconnecting said transconductive paths, a pair of base drive windings, each of said base drive windings connected in series with a respective one of said biasing paths, and a control winding, and switching means cooperating with said control winding to couple impedances to said primary windings to initiate reversal of current in said transformer windings, CHARACTERIZED IN THAT said control winding is tightly coupled to said base drive windings and loosely coupled to said primary winding, and said switching means operates to substantially short circuit said control winding, thereby reflecting a low impedance into said base drive windings and a higher inductive impedance into said primary winding.
Claim 5
Dependent Claim
28 words
An inverter as in claim 2 including a capacitor connected across said primary winding for resonating with said higher inductive impedance to facilitate said transformer winding current reversal.
Claim 6
Dependent Claim
36 words
An inverter as in claim 3 wherein said primary control and base drive windings are concentric, said control winding being spaced from said primary winding, and said base drive windings being imbedded in said Control winding.
Claim 7
Dependent Claim
37 words
An inverter as in claim 3 including the parallel combination of a diode and a capacitor connected in a path common to both of said biasing paths for preventing current overlap during commutation of said switching transistors.
Claim 8
Dependent Claim
39 words
An inverter as in claim 5 including a starting capacitor and a starting resistor connected in series between the center tap of said primary winding and the base of one of said switching transistors to reliably start said inverter.
Claim 9
Dependent Claim
204 words
A dc to dc converter comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a linear core portion and a saturating core portion, a center tapped primary winding wound on said linear core portion and interconnecting said transconductive paths, first and second base drive windings wound on said linear core portion, each of said base drive windings being connected in series with a respective biasing path, a control winding closely coupled to said base drive windings and loosely coupled to said primary winding, switching means connected across said control winding for periodically short circuiting said control winding to reflect a low impedance into said biasing windings and a higher inductive impedance into said primary winding and initiate reversal of current in said windings, an output winding wound on said saturating core portion, decoupling means partially decoupling said output windings from said primary winding, a ferrocapacitor coupled to said output winding, rectifying means connected to said output winding to provide a dc output, and feedback means connected between said dc output and said switching means for controlling the operation of said switching means in response to the voltage at said dc output to effect voltage regulation.
Claim 10
Dependent Claim
204 words
A dc to dc converter comprising a pair of switching transistors each having a transconductive path and a biasing path, a transformer having a linear core portion and a saturating core portion, a center tapped primary winding wound on said linear core portion and interconnecting said transconductive paths, first and second base drive windings wound on said linear core portion, each of said base drive windings being connected in series with a respective biasing path, a control winding closely coupled to said base drive windings and loosely coupled to said primary winding, switching means connected across said control winding for periodically short circuiting said control winding to reflect a low impedance into said biasing windings and a higher inductive impedance into said primary winding and initiate reversal of current in said windings, an output winding wound on said saturating core portion, decoupling means partially decoupling said output windings from said primary winding, a ferrocapacitor coupled to said output winding, rectifying means connected to said output winding to provide a dc output, and feedback means connected between said dc output and said switching means for controlling the operation of said switching means in response to the voltage at said dc output to effect voltage regulation.
Claim 11
Dependent Claim
92 words
A dc to dc converter as in claim 7 wherein said output winding has a center tap, said rectifying means provides a first output positive with respect to said center tap and a second output negative with respect to said center tap, and said feedback means includes first sensing means for sensing a change in said first output voltage, second sensing means for sensing a change in said second output voltage and switch control means responsive to both said first and second sensing means for controlling the operation of said switching means.
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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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |