US3714599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ladder termination circuit
Assignee: Motorola Solutions Inc
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Filing: 1971-03-24
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Granted: 1973-01-30
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Expires: 1991-03-24
Abstract
Abstract An improved and simplified termination circuit for the ladder portion of a digital to analog converter. the termination circuit includes an amplifier having unity current factor, known ladder termination voltage, and a very low impedance looking from the ladder into the amplifier.
Inventors
- 👤 J Cecil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:06
CPC Classifications
H; H03; H03M; H03M1/00; H03F; H03F3/00; H03F3/34; H03F3/343; H03M1/12; H03M1/48
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
165 words
An amplifier having unity current amplification between a first current supply terminal and a network terminal and which provides low resistance at said network terminal to circuits connected to said network terminal comprising first and second transistors each having a collector, an emitter and a base, constant current source means for feeding a constant current to the collector of said first transistor, means for connecting the collector of said first transistor to the base of said second transistor, means for connecting the base of said first transistor to the emitter of said second transistor, means for connecting the emitter of said first transistor to a bias terminal, switch means coupled between said first current supply terminal and the collector of said second transistor, a second current supply terminal, diode means coupled between said second current supply terminal and the collector of said second transistor, and means for connecting the base of said first transistor and the emitter of said second transistor to said network terminal.
Claim 2
Dependent Claim
165 words
An amplifier having unity current amplification between a first current supply terminal and a network terminal and which provides low resistance at said network terminal to circuits connected to said network terminal comprising first and second transistors each having a collector, an emitter and a base, constant current source means for feeding a constant current to the collector of said first transistor, means for connecting the collector of said first transistor to the base of said second transistor, means for connecting the base of said first transistor to the emitter of said second transistor, means for connecting the emitter of said first transistor to a bias terminal, switch means coupled between said first current supply terminal and the collector of said second transistor, a second current supply terminal, diode means coupled between said second current supply terminal and the collector of said second transistor, and means for connecting the base of said first transistor and the emitter of said second transistor to said network terminal.
Claim 3
Dependent Claim
165 words
An amplifier having unity current amplification between a first current supply terminal and a network terminal and which provides low resistance at said network terminal to circuits connected to said network terminal comprising first and second transistors each having a collector, an emitter and a base, constant current source means for feeding a constant current to the collector of said first transistor, means for connecting the collector of said first transistor to the base of said second transistor, means for connecting the base of said first transistor to the emitter of said second transistor, means for connecting the emitter of said first transistor to a bias terminal, switch means coupled between said first current supply terminal and the collector of said second transistor, a second current supply terminal, diode means coupled between said second current supply terminal and the collector of said second transistor, and means for connecting the base of said first transistor and the emitter of said second transistor to said network terminal.
Claim 4
Dependent Claim
165 words
An amplifier having unity current amplification between a first current supply terminal and a network terminal and which provides low resistance at said network terminal to circuits connected to said network terminal comprising first and second transistors each having a collector, an emitter and a base, constant current source means for feeding a constant current to the collector of said first transistor, means for connecting the collector of said first transistor to the base of said second transistor, means for connecting the base of said first transistor to the emitter of said second transistor, means for connecting the emitter of said first transistor to a bias terminal, switch means coupled between said first current supply terminal and the collector of said second transistor, a second current supply terminal, diode means coupled between said second current supply terminal and the collector of said second transistor, and means for connecting the base of said first transistor and the emitter of said second transistor to said network terminal.
Claim 5
Dependent Claim
71 words
The invention of claim 1 wherein said switch means comprises a third transistor, the emitter of which is connected to the collector of said second transistor, the collector of which is connected to the first current supply terminal and the base of which is adapted to receive switching signals, and said diode means is connected to conduct current from said second current supply terminal to the collector of said second transistor.
Claim 6
Dependent Claim
15 words
The invention of claim 1 in which said first and second transistors are NPN transistors.
Claim 7
Dependent Claim
17 words
The invention of claim 1 further including second constant current source means coupled to said network terminal.
Claim 8
Dependent Claim
70 words
The invention of claim 2 wherein said first, second and third transistors are NPN transistors and further including second constant current source means coupled to said network terminal to draw current therefrom, and said diode means comprises a diode with the anode thereof connected to said second current supply terminal and with the cathode thereof connected to the collector of said second transistor and the emitter of said third transistor.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |