US3789242A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overvoltage and undervoltage detection circuit
Assignee: AT&T Inc
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Filing: 1972-12-26
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Granted: 1974-01-29
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Expires: 1992-12-26
Abstract
Abstract An overvoltage and undervoltage detector circuit is disclosed in which two reference voltage producing circuits have their dissimilar outputs applied to first and second input terminals of a voltage comparator. The dissimilarity of the inputs to the comparator is reversed when a first voltage exceeding a predetermined level forward biases a first diode and raises the potential on one of the comparator input terminals or a second voltage less than a predetermined level forward biases a second diode and lowers the potential on the other comparator input terminal.
Inventors
- 👤 B Cantor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:12
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
221 words
A logic circuit comprising, a direct-current source, first and second series circuits each comprising a resistor and a diode and, furthermore each connected in a forward conducting sense across said source with said diodes connected to the same point on said source, a voltage comparator having first and second input terminals and an output terminal, a direct-current path connected between said comparator first input terminal and the junction between the resistor and the diode of said first series circuit, a third diode connected between said comparator second input terminal and the junction between the resistor and the diode of said second series circuit with said third diode having the same type of electrode terminal connected to said second series circuit junction as the diode in said second series circuit, first and second input terminals for said logic circuit, a fourth diode connected between said logic circuit first input terminal and said comparator second input terminal with said fourth diode having the same type of electrode terminal connected to said comparator second input terminal as said third diode, and a fifth diode connected between said logic circuit second input terminal and said comparator first input terminal with said fifth diode having the same type of electrode terminal connected to said comparator first input terminal as the diode in said first series circuit.
Claim 2
Dependent Claim
221 words
A logic circuit comprising, a direct-current source, first and second series circuits each comprising a resistor and a diode and, furthermore each connected in a forward conducting sense across said source with said diodes connected to the same point on said source, a voltage comparator having first and second input terminals and an output terminal, a direct-current path connected between said comparator first input terminal and the junction between the resistor and the diode of said first series circuit, a third diode connected between said comparator second input terminal and the junction between the resistor and the diode of said second series circuit with said third diode having the same type of electrode terminal connected to said second series circuit junction as the diode in said second series circuit, first and second input terminals for said logic circuit, a fourth diode connected between said logic circuit first input terminal and said comparator second input terminal with said fourth diode having the same type of electrode terminal connected to said comparator second input terminal as said third diode, and a fifth diode connected between said logic circuit second input terminal and said comparator first input terminal with said fifth diode having the same type of electrode terminal connected to said comparator first input terminal as the diode in said first series circuit.
Claim 3
Dependent Claim
252 words
A logic circuit comprising, a bridge circuit comprising first, second, third, and fourth terminals with a first resistor connected between said first and second terminals, a second resistor connected between said first and third terminals, a first diode connected between said second and fourth terminals, and a second diode connected between said third and fourth terminals, where said diodes have the same type of electrode terminal connected to said fourth terminal, a direct-current source connected to said first and fourth terminals in a polarity sense to cause a current to flow through said first and second diodes, a voltage comparator having first and second input terminals and an output terminal, a direct-current path connected between said comparator first input terminal and said bridge circuit second terminal, a third diode connected between said bridge circuit third terminal and said comparator second input terminal with said third diode having the same type of electrode terminal connected to said bridge circuit third terminal as said second diode, first and second input terminals for said logic circuit, a fourth diode connected between said logic circuit first input terminal and said comparator second input terminal with said fourth diode having the same type of electrode terminal connected to said comparator second input terminal as said third diode, and a fifth diode connected between said logic circuit second input terminal and said comparator first input terminal with said fifth diode having the same type of electrode terminal connected to said comparator first input terminal as said first diode.
Claim 4
Dependent Claim
252 words
A logic circuit comprising, a bridge circuit comprising first, second, third, and fourth terminals with a first resistor connected between said first and second terminals, a second resistor connected between said first and third terminals, a first diode connected between said second and fourth terminals, and a second diode connected between said third and fourth terminals, where said diodes have the same type of electrode terminal connected to said fourth terminal, a direct-current source connected to said first and fourth terminals in a polarity sense to cause a current to flow through said first and second diodes, a voltage comparator having first and second input terminals and an output terminal, a direct-current path connected between said comparator first input terminal and said bridge circuit second terminal, a third diode connected between said bridge circuit third terminal and said comparator second input terminal with said third diode having the same type of electrode terminal connected to said bridge circuit third terminal as said second diode, first and second input terminals for said logic circuit, a fourth diode connected between said logic circuit first input terminal and said comparator second input terminal with said fourth diode having the same type of electrode terminal connected to said comparator second input terminal as said third diode, and a fifth diode connected between said logic circuit second input terminal and said comparator first input terminal with said fifth diode having the same type of electrode terminal connected to said comparator first input terminal as said first diode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |