US3900790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant current circuit
Assignee: Sony Corp
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Filing: 1973-06-01
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Granted: 1975-08-19
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Expires: 1993-06-01
Abstract
Abstract The circuit is designed to produce a substantially constant current from a source of voltage which is subject to variations and includes first and second transistors of opposite conductivity types, the base of each transistor being connected to the collector electrode of the opposite transistor and the emitter electrodes of the two transistors being connected to opposite terminals of a voltage source, a pair of diode means separately connected in parallel between the emitter and base electrodes of each of the first and second transistors, respectively, and a third transistor whose base and emitter electrodes are connected in parallel between the base and emitter electrodes of the first or second transistor, whereby the collector current of the third transistor is utilized as a constant current source which is not subject to changes because of fluctuations of the source voltage.
Inventors
- 👤 Mitsuo Ohsawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:10
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/30; H03F1/307; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/22; G05F3/222; G05F3/227; H03F3/00; H03F3/30; H03F3/3083; H03F3/3086
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
245 words
In combination an amplifier circuit having a constant current circuit as a load therefor, comprising: a first amplifying transistor having an input electrode supplied with a signal to be amplified and an output electrode, the first amplifying transistor being connected in a grounded emitter type configuration; a second amplifying transistor having an output electrode and an input electrode connected to the output electrode of the first amplifying transistor, the second amplifying transistor being connected in a grounded collector type configuration; a voltage source having at least two output terminals; first and second transistors, the base and collector electrodes of the first transistor being respectively connected to the collector and base electrodes of the second transistor, the respective emitter electrodes of the first and second transistors being connected to separate terminals of the voltage source; third and fourth unidirectional conducting devices for providing biasing voltages between the base and emitter electrodes of each of the first and second transistors; at least one further transistor, the base and emitter electrodes of said at least one further transistor being connected to the base and emitter electrodes of a corresponding one of the first and second transistors; whereby the collector current of said at least one further transistor with respect to the voltage source is utilizable as a constant current source; and the collector electrode of said at least one further transistor being connected to the output electrode of a corresponding one of the first and second amplifying transistors.
Claim 2
Dependent Claim
245 words
In combination an amplifier circuit having a constant current circuit as a load therefor, comprising: a first amplifying transistor having an input electrode supplied with a signal to be amplified and an output electrode, the first amplifying transistor being connected in a grounded emitter type configuration; a second amplifying transistor having an output electrode and an input electrode connected to the output electrode of the first amplifying transistor, the second amplifying transistor being connected in a grounded collector type configuration; a voltage source having at least two output terminals; first and second transistors, the base and collector electrodes of the first transistor being respectively connected to the collector and base electrodes of the second transistor, the respective emitter electrodes of the first and second transistors being connected to separate terminals of the voltage source; third and fourth unidirectional conducting devices for providing biasing voltages between the base and emitter electrodes of each of the first and second transistors; at least one further transistor, the base and emitter electrodes of said at least one further transistor being connected to the base and emitter electrodes of a corresponding one of the first and second transistors; whereby the collector current of said at least one further transistor with respect to the voltage source is utilizable as a constant current source; and the collector electrode of said at least one further transistor being connected to the output electrode of a corresponding one of the first and second amplifying transistors.
Claim 3
Dependent Claim
64 words
The combination of claim 1 and further comprising a second further transistor, the base and emitter electrodes of said second further transistor being connected to the base and emitter electrodes of the outer of said first and second transistors; and the collector electrode of said second further transistor being connected to the output electrode of the other of said first and second amplifying transistors.
Claim 4
Dependent Claim
49 words
The combination of claim 2 and further comprising an input amplifying circuit for supplying said signal to be amplified to said first amplifying transistor input electrode; and a feedback circuit for connecting the output electrode of said second amplifying transistor to said input amplifying circuit in negative feedback relation.
References Cited (Backward Citations)
US3522521A
Cited
US3392344A
Cited
US3555309A
Cited
US3617859A
Cited
US3651347A
Cited
US3648153A
Cited
US3777251A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |