US3612909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistorized switching circuit
Assignee: Shinko Electric Co Ltd
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Filing: 1970-06-08
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Granted: 1971-10-12
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Expires: 1990-06-08
Abstract
Abstract A transistorized circuit for providing switching action includes main switching transistors and prestage transistors. The circuit also includes a multiwinding current transformer, the primary windings of which are connected in the main switching circuit so that the secondary outputs of the current transformer may be used to obtain driving sources for the prestage transistors. In a preferred embodiment, driving currents sufficient to cause the main switching transistors to full-saturate are always supplied to the prestage transistors by back-to-back diode circuits.
Inventors
- 👤 Hirosuke Imabayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:11
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/538; H02M7/5381; H03; H03K; H03K3/00; H03K3/02; H03K3/26; H03K3/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
122 words
In a switching circuit of the type which has at least two main switching transistors and in which prestage transistors are associated with the main transistors so that, by the application of control signals to the bases of said prestage transistors, said main circuit transistors provide switching action, the improvement which comprises a current transformer connected in the main circuit, the outputs of said current transformer being utilized to provide driving sources for said prestage transistors, and at least two back-to-back diode circuits inserted between the collectors of said main circuit transistors and the output terminals of the secondary windings of said current transformer, wherein driving currents are supplied to said prestage transistors through forward biased junctions of said back-to-back diode circuits.
Claim 2
Dependent Claim
122 words
In a switching circuit of the type which has at least two main switching transistors and in which prestage transistors are associated with the main transistors so that, by the application of control signals to the bases of said prestage transistors, said main circuit transistors provide switching action, the improvement which comprises a current transformer connected in the main circuit, the outputs of said current transformer being utilized to provide driving sources for said prestage transistors, and at least two back-to-back diode circuits inserted between the collectors of said main circuit transistors and the output terminals of the secondary windings of said current transformer, wherein driving currents are supplied to said prestage transistors through forward biased junctions of said back-to-back diode circuits.
Claim 3
Dependent Claim
176 words
A switching circuit comprising a power transformer, for providing AC power to an external load, said transformer having a center tapped primary winding, and a secondary winding; at least two switching transistors connected in series with said at least two primary windings across the primary winding of said power transformer; at least two prestage transistors, each connected in series with one of said secondary windings of the current transformer and with a diode between the common junction point of said two switching transistors and the base electrode of the corresponding switching transistor, said prestage transistors being driven alternately by an input applied to their base electrodes, and two diodes, each connected between the junction between the primary winding of the power transformer and the corresponding switching transistor and the junction between the corresponding prestage transistor and the corresponding diode connected adjacent thereto, wherein by application of DC power between said common junction point and the center tap of the power transformer, AC power is supplied to a load through the secondary winding of said power transformer.
Claim 4
Dependent Claim
176 words
A switching circuit comprising a power transformer, for providing AC power to an external load, said transformer having a center tapped primary winding, and a secondary winding; at least two switching transistors connected in series with said at least two primary windings across the primary winding of said power transformer; at least two prestage transistors, each connected in series with one of said secondary windings of the current transformer and with a diode between the common junction point of said two switching transistors and the base electrode of the corresponding switching transistor, said prestage transistors being driven alternately by an input applied to their base electrodes, and two diodes, each connected between the junction between the primary winding of the power transformer and the corresponding switching transistor and the junction between the corresponding prestage transistor and the corresponding diode connected adjacent thereto, wherein by application of DC power between said common junction point and the center tap of the power transformer, AC power is supplied to a load through the secondary winding of said power transformer.
Claim 5
Dependent Claim
40 words
A switching circuit as specified in claim 2, wherein the turns ratio of the primary and secondary windings of the current transformer are selected to be larger than the reciprocal of the current amplification factor of the switching transistor 5.
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) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |