Patent JPS5544772A successfully refreshed from Google Patents.
US4716356A
Expired / Lapsed
US
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JFET pinch off voltage proportional reference current generating circuit
Assignee: Motorola Solutions Inc
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Filing: 1986-12-19
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Granted: 1987-12-29
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Expires: 2006-12-19
Abstract
Abstract A circuit for generating a reference current proportional over temperature to the pinch-off voltage of a first JFET includes second and third JFETS and first and second resistors. The second JFET has its gate coupled to its source and produces a current which drives the first JFET. Since the width-to-length ratio of the second JFET is greater than that of the first, a negative gate-to-source voltage of the first JFET is produced across the first resistor. The third JFET has a source coupled via the second resistor to the gate of the first JFET and has a gate coupled to the drain of the first JFET for setting the voltage thereat. The reference current appears at the drain of the third JFET.
Inventors
- 👤 Robert L. Vyne
- 👤 David M. Susak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:24
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: 5
Claim 1
Independent Claim
108 words
A circuit for generating a reference current proportional over temperature to the ratio of the pinch off voltage V p of a JFET to some resistance, comprising: a first JFET having a source coupled to a first source of supply voltage, a gate, and a drain; first means coupled to the drain of said first JFET for imparting a negative gate-to-source voltage on said first JFET; first resistive means coupled between the gate and source of said first JFET for producing said reference current; and second means coupled to the gate and drain of said first JFET for setting the voltage at the drain of said first JFET.
Claim 2
Dependent Claim
108 words
A circuit for generating a reference current proportional over temperature to the ratio of the pinch off voltage V p of a JFET to some resistance, comprising: a first JFET having a source coupled to a first source of supply voltage, a gate, and a drain; first means coupled to the drain of said first JFET for imparting a negative gate-to-source voltage on said first JFET; first resistive means coupled between the gate and source of said first JFET for producing said reference current; and second means coupled to the gate and drain of said first JFET for setting the voltage at the drain of said first JFET.
Claim 3
Dependent Claim
41 words
A circuit according to claim 1 wherein said first means comprises a second JFET having a gate and source coupled together and to the drain of said first JFET and having a drain coupled to a second source of supply voltage.
Claim 4
Dependent Claim
23 words
A circuit according to claim 2 wherein the width-to-length ratio of said first JFET is less than the that of said second JFET.
Claim 5
Dependent Claim
61 words
A circuit according to claim 3 wherein said second means comprises: second resistive means having a first terminal coupled to the gate of said first JFET; and a third JFET having a source coupled to the second terminal of said second resistive means, a gate coupled to the drain of said first JFET and a drain for conducting said reference current.
References Cited (Backward Citations)
US4449067A
Cited
US4645998A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |