US3699358A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current sharing parallel transistor circuit
Assignee: Pioneer Magnetics Inc
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Filing: 1971-06-14
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Granted: 1972-10-17
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Expires: 1991-06-14
Abstract
Abstract An improved circuit is provided effectively to connect a plurality of power transistors in a parallel connection for handling power levels beyond the capabilities of the individual transistors. The circuit includes a transformer intercoupling the emitters of the individual transistors for current sharing purposes, and for insuring equal current division among the individual transistors during continuous operation thereof, and during intermittent ''''on-off'''' operation thereof when the transistors are used for switching purposes.
Inventors
- 👤 Bruce L Wilkinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:28
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
154 words
A transistor system providing a parallel combination of a plurality of transistors, and also providing equal current division between the transistors during normal conductive periods and during turn-off operations of the transistors, said circuit comprising: three transistors each having base, emitter and collector electrodes; a first transformer intercoupling the emitter electrodes of two of said three transistors, said first transformer having a first winding connected to the emitter electrode of one of the two transistors and having a second winding connected to the emitter electrode of the other of the three transistors; common circuitry connecting the other side of said first and second wiNdings of said first transformer to a common potential point; and a second transformer interposed in said common circuitry and having first and second windings with a turns ratio of 2:1, said first winding of said second transformer being connected to the emitter of the remaining one of said three transistors.
Claim 2
Dependent Claim
154 words
A transistor system providing a parallel combination of a plurality of transistors, and also providing equal current division between the transistors during normal conductive periods and during turn-off operations of the transistors, said circuit comprising: three transistors each having base, emitter and collector electrodes; a first transformer intercoupling the emitter electrodes of two of said three transistors, said first transformer having a first winding connected to the emitter electrode of one of the two transistors and having a second winding connected to the emitter electrode of the other of the three transistors; common circuitry connecting the other side of said first and second wiNdings of said first transformer to a common potential point; and a second transformer interposed in said common circuitry and having first and second windings with a turns ratio of 2:1, said first winding of said second transformer being connected to the emitter of the remaining one of said three transistors.
Claim 3
Dependent Claim
18 words
The system defined in claim 1, and which includes circuitry interconnecting the base electrodes of said three transistors.
Claim 4
Dependent Claim
18 words
The system defined in claim 1, and which includes circuitry interconnecting the collector electrodes of said three transistors.
Claim 5
Dependent Claim
34 words
The system defined in claim 1, in which said first and second transformers each comprises an annular ferrite core, and in which said windings of each of said transformers are wound on said core.
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) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |