US3660724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power supply protective control
Assignee: Pioneer Magnetics Inc
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Filing: 1971-03-18
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Granted: 1972-05-02
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Expires: 1991-03-18
Abstract
Abstract An improved protective circuit provided by which a silicon controlled rectifier (SCR), or equivalent device, is switched into circuit with a power supply in the presence of excessive output voltage, so as to protect the electronic equipment which is normally energized by the power supply. The protective circuit of the invention is such that the silicon controlled rectifier is not subjected to excessive currents so that it need not be excessively large, and no heat sink is required in conjunction with the silicon controlled rectifier.
Inventors
- 👤 James K Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:50
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H9/00; H02H9/04; H02H9/041; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/338; H02M3/3385
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
225 words
A power supply circuit including: a first transformer having a primary winding and a secondary winding; a second transformer having a primary winding and a secondary winding; a unidirectional potential source connected to one side of the primary winding of said first transformer and to one side of the secondary winding of said second transformer; a switching transistor having a base electrode connected to the other side of the secondary winding of said second transformer, and a collector electrode connected to the other side of the primary of said first transformer, and an emitter electrode connected to a tap on the secondary winding of said second transformer; an output circuit connected to the secondary winding of said first transformer for developing an output voltage; a control circuit connected to the primary winding of the second transformer for cyclically controlling the conductivity of said transistor to maintain said output voltage at a predetermined regulated level; and a protective circuit including a silicon controlled rectifier connected across the primary winding of said second transformer to short circuit said last-named primary winding whenever said silicon controlled rectifier is fired so as to prevent said transistor from being rendered conductive, and said silicon rectifier having a gate electrode connected to said output circuit to cause said silicon controlled rectifier to fire whenever the output voltage exceeds a predetermined threshold.
Claim 2
Dependent Claim
225 words
A power supply circuit including: a first transformer having a primary winding and a secondary winding; a second transformer having a primary winding and a secondary winding; a unidirectional potential source connected to one side of the primary winding of said first transformer and to one side of the secondary winding of said second transformer; a switching transistor having a base electrode connected to the other side of the secondary winding of said second transformer, and a collector electrode connected to the other side of the primary of said first transformer, and an emitter electrode connected to a tap on the secondary winding of said second transformer; an output circuit connected to the secondary winding of said first transformer for developing an output voltage; a control circuit connected to the primary winding of the second transformer for cyclically controlling the conductivity of said transistor to maintain said output voltage at a predetermined regulated level; and a protective circuit including a silicon controlled rectifier connected across the primary winding of said second transformer to short circuit said last-named primary winding whenever said silicon controlled rectifier is fired so as to prevent said transistor from being rendered conductive, and said silicon rectifier having a gate electrode connected to said output circuit to cause said silicon controlled rectifier to fire whenever the output voltage exceeds a predetermined threshold.
Claim 3
Dependent Claim
45 words
The power supply circuit defined in claim 1, and which includes said gate electrode to determine the voltage level at a Zener diode interposed between said output circuit and said gate electrode to determine the voltage level at which said silicon controlled rectifier will fire.
Claim 4
Dependent Claim
52 words
The power supply circuit defined in claim 1, and which includes a Zener diode connected between the primary winding of said second transformer and the gate electrode of said silicon controlled rectifier to cause said silicon controlled rectifier to fire whenever the voltage across the last-mentioned primary winding exceeds a predetermined value.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |