US4639617A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable-bias circuit with HF transmission path
Assignee: US Philips Corp
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Filing: 1985-04-15
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Granted: 1987-01-27
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Expires: 2005-04-15
Abstract
Abstract On an output terminal (12) of a variable-bias circuit with an HF transmission path a bias voltage (Vo) is produced which is variable in response to variations of a d.c. control voltage (Vc) applied to a control terminal (13). The circuit transmits an HF signal from an input terminal (14) to the output terminal (12) with a low attenuation. In accordance with the invention this circuit comprises a field-effect transistor (11) whose source (S1) is driven by a constant-current generator (22) and is connected to the output terminal (12), the grate (G1) of the transistor (11) being connected to the control terminal (13) by a resistor (R1) and to the source (S1) of the transistor (11) by a capacitive element (16).
Inventors
- 👤 Alex Giakoumis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:01
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/24; H; H01; H01P; H01P1/00; H01P1/20; H03; H03H; H03H11/00; H03H11/46; H03H11/48
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
134 words
A variable-bias circuit with an HF transmission path, having an output terminal (12) on which a variable bias voltage (Vo) is produced in response to variations of a d.c. control voltage (Vc) applied to a control terminal (13), which variable-bias circuit transmits an HF signal from an input terminal (14) to the output terminal (12) with a low attenuation, said input terminal and output terminal being interconnected by a decoupling capacitor (15), characterized in that said variable-bias circuit comprises a first field-effect transistor (11) whose source (S1) is driven by a constant-current generator (22) and is connected to the output terminal (12), the gate (G1) of the transistor (11) being connected to the control terminal (13) via a resistor (R1) and to the source (S1) of the transistor (11) via a capacitive element (16).
Claim 2
Dependent Claim
134 words
A variable-bias circuit with an HF transmission path, having an output terminal (12) on which a variable bias voltage (Vo) is produced in response to variations of a d.c. control voltage (Vc) applied to a control terminal (13), which variable-bias circuit transmits an HF signal from an input terminal (14) to the output terminal (12) with a low attenuation, said input terminal and output terminal being interconnected by a decoupling capacitor (15), characterized in that said variable-bias circuit comprises a first field-effect transistor (11) whose source (S1) is driven by a constant-current generator (22) and is connected to the output terminal (12), the gate (G1) of the transistor (11) being connected to the control terminal (13) via a resistor (R1) and to the source (S1) of the transistor (11) via a capacitive element (16).
Claim 3
Dependent Claim
45 words
A circuit as claimed in claim 1, characterized in that the constant-current generator (22) comprises a second field-effect transistor whose current ((I DS ) 2 ) between the drain (D2) and the source (S2) remains substantially constant during variations of the d.c. control voltage (Vc).
Claim 4
Dependent Claim
39 words
A circuit as claimed in claim 2, characterized in that in the case of equal channel lengths the channel width of the first field-effect transistor (11) is at least equal to the channel width the second field-effect transistor (22).
Claim 5
Dependent Claim
26 words
A circuit as claimed in any one of the claims 1 to 3, characterized in that the capacitive element (16) is constituted by a reverse-biased diode.
References Cited (Backward Citations)
US3539834A
Cited
US3621284A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-26 | 1990-07-28 | 1991-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-26 | 1994-07-28 | 1995-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-26 | 1998-07-28 | 1999-01-27 | $7700.00 | Window Closed / Lapsed |