US3748569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Regulated short circuit protected power supply
Assignee: United States Department of the Army
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Filing: 1972-04-13
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Granted: 1973-07-24
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Expires: 1992-04-13
Abstract
Abstract A voltage regulated power supply utilizing a small series resistance to sense load current and a circuit including a normally ''''off'''' trigger transistor having its base connected to the load side of the series resistor for actuation to ''''on'''' condition responsive to voltage drop in the resistor and a series switching transistor having its base connected to the output of the trigger transistor to shut off the series switching transistor in an overload condition which in turn interrupts operation of a series transistor by interrupting base current thereto. The circuit also includes a latching zener diode connected to the base of the trigger transistor to maintain its ''''on'''' condition after overload to maintain the power supply inoperative until the fault is removed and the supply is recycled.
Inventors
- 👤 G Frank
- 👤 J Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:08
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/56; G05F1/565; G05F1/569; G05F1/573
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
205 words
In a voltage regulated power supply for connection to a voltage source and a voltage regulated load output line and employing a series regulating transistor having a base and connected to pass current to the load line, and a current source amplifying transistor having a base and connected to pass a regulating current to the base of the series regulating transistor together with a reference voltage zener diode connected to the base of said current source transistor and to ground, an improved overload circuit means providing short circuit protection for said power supply circuit comprising in combination: a. a series switching transistor having a base and being connected to pass the output of said current source transistor to the base of said series regulating transistor to control the base current on the latter, b. a sensing resistor connected in series with the voltage source to carry load current, c. a trigger transistor connected to tHe source and to the base of said series switching transistor, d. said trigger transistor having its base connected to the load side of said sensing resistor to shut off base current to said series switching transistor to remove base drive from the series regulating transistor responsive to an overload condition.
Claim 2
Dependent Claim
205 words
In a voltage regulated power supply for connection to a voltage source and a voltage regulated load output line and employing a series regulating transistor having a base and connected to pass current to the load line, and a current source amplifying transistor having a base and connected to pass a regulating current to the base of the series regulating transistor together with a reference voltage zener diode connected to the base of said current source transistor and to ground, an improved overload circuit means providing short circuit protection for said power supply circuit comprising in combination: a. a series switching transistor having a base and being connected to pass the output of said current source transistor to the base of said series regulating transistor to control the base current on the latter, b. a sensing resistor connected in series with the voltage source to carry load current, c. a trigger transistor connected to tHe source and to the base of said series switching transistor, d. said trigger transistor having its base connected to the load side of said sensing resistor to shut off base current to said series switching transistor to remove base drive from the series regulating transistor responsive to an overload condition.
Claim 3
Dependent Claim
74 words
Apparatus according to claim 1, including a. a latching zener diode connected to the base of said trigger transistor and to said regulated output line to maintain an ''''on'''' bias for said trigger transistor when the actuating bias of said sensing resistor is removed therefrom by inactivation of said series regulating transistor thereby to automatically maintain said power supply in inoperative condition until the load short is removed and the circuit recycled for operation.
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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |