US3621281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear rise and fall time current generator
Assignee: Ferroxcube Corp
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Filing: 1969-09-12
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Granted: 1971-11-16
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Expires: 1989-09-12
Abstract
Abstract A current source having a linear rise and fall time which uses a pair of oppositely polarized constant current sources connected to a capacitor to control an emitter follower and a common base amplifier. Alternately activating and deactivating one of the constant current sources produces a linear rise and fall in the charge on the capacitor, which is reflected in a linear rise and fall in the output current of the common base amplifier.
Inventors
- 👤 Thomas E Hagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:28
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
233 words
Apparatus for providing linearly rising and falling currents for a variable impedance load, comprising first current source means for providing a constant current to an output terminal of said first current source means, second current source means for providing a constant current of a greater magnitude and in the opposite sense of said current from said first current source means to an output terminal of said second current source means in response to a turn-on pulse, integrating means connected to the output terminal of said first and said second current sources for converting the currents from said first and said second current source means into a linearly rising and falling voltage, and amplifier means connected to said integrating means for converting said voltage from said integrating means into a linearly rising and falling current, said amplifying means comprising a first transistor having a base, an emitter, and a collector terminal, means for connecting said base terminal of said first transistor to said integrating means, means for connecting said collector of said first transistor to a first bias voltage, a second transistor having a base, an emitter and a collector terminal, means for connecting the base of said second transistor to a second bias voltage, a resistor, and means for connecting the emitter terminal of said first transistor to said load through said resistor and said emitter and collector terminals of said second transistor.
Claim 2
Dependent Claim
233 words
Apparatus for providing linearly rising and falling currents for a variable impedance load, comprising first current source means for providing a constant current to an output terminal of said first current source means, second current source means for providing a constant current of a greater magnitude and in the opposite sense of said current from said first current source means to an output terminal of said second current source means in response to a turn-on pulse, integrating means connected to the output terminal of said first and said second current sources for converting the currents from said first and said second current source means into a linearly rising and falling voltage, and amplifier means connected to said integrating means for converting said voltage from said integrating means into a linearly rising and falling current, said amplifying means comprising a first transistor having a base, an emitter, and a collector terminal, means for connecting said base terminal of said first transistor to said integrating means, means for connecting said collector of said first transistor to a first bias voltage, a second transistor having a base, an emitter and a collector terminal, means for connecting the base of said second transistor to a second bias voltage, a resistor, and means for connecting the emitter terminal of said first transistor to said load through said resistor and said emitter and collector terminals of said second transistor.
Claim 3
Dependent Claim
57 words
Apparatus as claimed in claim 1 wherein said integrating means comprises a capacitor, means for connecting one side of said capacitor to said second bias voltage and means for connecting the other side of said capacitor to the base terminal of said first transistor and to the output terminals of said first and said second current sources.
Claim 4
Dependent Claim
41 words
Apparatus as claimed in claim 2 wherein said integrating means further comprises a diode connected across said capacitor and having a forward direction of conductivity opposing the forward direction of conductivity of the base to emitter path of said first transistor.
Claim 5
Dependent Claim
55 words
Apparatus as claimed in claim 1, wherein said first current source comprises a third transistor having base, emitter and collector terminals, a zener diode connected across the base and emitter terminals of said third transistor, and means for connecting the collector terminal of said third transistor to said output terminal of said first current source.
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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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |