Patent US2810552A successfully refreshed from Google Patents.
Patent US4508976A successfully refreshed from Google Patents.
US4508976A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adjustable frequency drive
Assignee: Siemens Energy and Automation Inc
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Filing: 1983-01-14
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Granted: 1985-04-02
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Expires: 2003-01-14
Abstract
Abstract A circuit for driving a power transistor that forms a part of an inverter circuit used in motor control in which the circuit is switched at high voltages. The motor drive circuit isolates and amplifies a control signal so as to operate the power switching transistors. The base drive circuit employs two characteristics of power transistors to derive maximum protection and maximum performance simultaneously. This control is accomplished by sensing both the collector-to-emitter voltage of the power transistor as well as the base-to-emitter voltage thereof. In an alternate embodiment described herein, a feedback circuit is also provided sensitive to collector-to-emitter voltage for shortening the try-time associated with the power transistor.
Inventors
- 👤 Mark R. Hickman
- 👤 Michael M. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:36
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0826
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
198 words
A circuit for driving a biased power transistor that is adapted to switch high voltages and that has an input electrode and a pair of output electrodes comprising emitter and collector electrodes, said circuit comprising; input circuit means for receiving an input control signal for switching said power transistor, control transistor means coupled from said input circuit means having drive and non-drive states and having its output coupled to the input electrode of said power transistor, first means, responsive to the magnitude of the power transistor collector-to-emitter voltage exceeding a predetermined threshold, for decreasing drive current from the control transistor means to the power transistor, second means, responsive to the magnitude of the power transistor base-to-emitter voltage exceeding a predetermined threshold under overload conditions, for decreasing drive current from the control transistor means to the power transistor, third means, responsive to the magnitude of the power transistor collector-to-emitter voltage being below a predetermined reference level, for decreasing drive current to the power transistor for maintaining the power transistor in a non-saturated condition, and fourth means, responsive to the magnitude of the power transistor collector-to-emitter voltage for decreasing the power transistor try-time under heavy overload or short circuit conditions.
Claim 2
Dependent Claim
198 words
A circuit for driving a biased power transistor that is adapted to switch high voltages and that has an input electrode and a pair of output electrodes comprising emitter and collector electrodes, said circuit comprising; input circuit means for receiving an input control signal for switching said power transistor, control transistor means coupled from said input circuit means having drive and non-drive states and having its output coupled to the input electrode of said power transistor, first means, responsive to the magnitude of the power transistor collector-to-emitter voltage exceeding a predetermined threshold, for decreasing drive current from the control transistor means to the power transistor, second means, responsive to the magnitude of the power transistor base-to-emitter voltage exceeding a predetermined threshold under overload conditions, for decreasing drive current from the control transistor means to the power transistor, third means, responsive to the magnitude of the power transistor collector-to-emitter voltage being below a predetermined reference level, for decreasing drive current to the power transistor for maintaining the power transistor in a non-saturated condition, and fourth means, responsive to the magnitude of the power transistor collector-to-emitter voltage for decreasing the power transistor try-time under heavy overload or short circuit conditions.
Claim 3
Dependent Claim
26 words
A circuit as set forth in claim 1 wherein said first means includes a first unilateral means for conducting when the collector-to-emitter voltage exceeds said threshold.
Claim 4
Dependent Claim
26 words
A circuit as set forth in claim 2 wherein said second means includes a second unilateral means for conducting when the base-to-emitter voltage exceeds the threshold.
Claim 5
Dependent Claim
28 words
A circuit as set forth in claim 3 wherein said input circuit means comprises a comparator means and said control transistor means comprises at least one drive transistor.
Claim 6
Dependent Claim
28 words
A circuit as set forth in claim 4 wherein said first unilateral means couples to the base of said drive transistor to divert base drive from said transistor.
Claim 7
Dependent Claim
22 words
A circuit as set forth in claim 5 including means coupling the second unilateral means to the base of said drive transistor.
Claim 8
Dependent Claim
27 words
A circuit as set forth in claim 6 including a pair of comparators and a second transistor, said comparators coupling to respective first and second drive transistors.
Claim 9
Dependent Claim
39 words
A circuit as set forth in claim 7 wherein said first unilateral means couples to the power transistor collector and the second unilateral means couples to the power transistor base by way of the first drive transistor base-to-emitter junction.
Claim 10
Dependent Claim
32 words
A circuit as set forth in claim 8 including a third unilateral means coupled from the collector of the power transistor to the input of said comparators to hold the comparators latched.
Claim 11
Dependent Claim
23 words
A circuit as set forth in claim 9 wherein the first means is operative at a lower collector current than the second means.
Claim 12
Dependent Claim
40 words
A circuit as set forth in claim 1 wherein said first means comprises means responsive to the magnitude of the collector-to-emitter voltage exceeding a predetermined threshold for turning off and reverse biasing the power transistor after a fixed delay time.
Claim 13
Dependent Claim
34 words
A circuit as set forth in claim 1 including fourth means, responsive to the magnitude of the power transistor collector-to-emitter voltage for decreasing the power transistor try-time under heavy overload or short circuit conditions.
Claim 14
Dependent Claim
32 words
A circuit as set forth in claim 1 wherein said fourth means comprises at least one resistor coupled from said power transistor in a feedback circuit back to said input circuit means.
Claim 15
Dependent Claim
32 words
A circuit as set forth in claim 13 wherein said input circuit means includes capacitor means with said fourth means coupling to said capacitor means for changing the charge time constant thereof.
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) | 1988-04-01 | 1988-10-01 | 1989-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-01 | 1992-10-01 | 1993-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-01 | 1996-10-01 | 1997-04-02 | $7700.00 | Window Closed / Lapsed |