US4642552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilized current source circuit
Assignee: Hitachi Ltd
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Filing: 1986-02-10
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Granted: 1987-02-10
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Expires: 2006-02-10
Abstract
Abstract For realizing a stabilized current source circuit providing a stabilized current which is insensitive to a change in the threshold voltage of a MOS transistor, a gate electrode of a first MOS transistor feeding a drain current as a constant current output is supplied with the sum of the gate-source voltage of a second MOS transistor and the potential of a stabilized voltage source.
Inventors
- 👤 Toshiro Suzuki
- 👤 Osamu Matsubara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:42
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/24; G05F3/242; G05F3/245
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
A stabilized current source circuit comprising: a first MOS transistor feeding a drain current to be used as a constant current output; a second MOS transistor having a gate electrode connected to a gate electrode of said first MOS transistor; a current source connected to the drain electrode of said second MOS transistor; and a stabilized voltage source connected to the source of said second MOS transistor so as to keep the gate-source voltage of said second MOS transistor at a value which is closer to a threshold voltage value than the gate-source voltage of said first MOS transistor.
Claim 2
Dependent Claim
99 words
A stabilized current source circuit comprising: a first MOS transistor feeding a drain current to be used as a constant current output; a second MOS transistor having a gate electrode connected to a gate electrode of said first MOS transistor; a current source connected to the drain electrode of said second MOS transistor; and a stabilized voltage source connected to the source of said second MOS transistor so as to keep the gate-source voltage of said second MOS transistor at a value which is closer to a threshold voltage value than the gate-source voltage of said first MOS transistor.
Claim 3
Dependent Claim
25 words
A stabilized current source circuit according to claim 1, wherein the drain electrode of said second MOS transistor is connected to the gate electrode thereof.
Claim 4
Dependent Claim
35 words
A stabilized current according to claim 2, wherein the voltage of said stabilized voltage source is 200 to 300 mV and the current of said current source is 1/10 to 1/100 times the drain current.
Claim 5
Dependent Claim
18 words
A stabilized current source circuit according to claim 2, wherein said current source comprises a current mitter circuit.
Claim 6
Dependent Claim
138 words
A stabilized current source circuit according to claim 4, wherein said current mitter circuit includes third and fourth MOS transistors respectively having drain electrodes connected together and to a common power source of a first potential value and having gate electrodes connected together, and said current miller circuit also includes a fifth MOS transistor having a source electrode which is connected to another power source of a second potential value together with the source electrode of said first MOS transistor, and wherein a source electrode of said third MOS transistor is connected to the drain electrode of said second MOS transistor, and the gate electrode of said fourth MOS transistor, a gate electrode of said fifth MOS transistor, a source electrode of said fourth MOS transistor, and the drain electrode of said fifth MOS transistor are connected together.
Claim 7
Dependent Claim
19 words
A stabilized current source circuit according to claim 3, wherein said stabilized voltage source comprises a band-gap reference circuit.
References Cited (Backward Citations)
JPS51138848A
Cited
US4020367A
Cited
US4327321A
Cited
JPS5644917A
Cited
JPS56121114A
Cited
US4399374A
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |