US3655996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective circuit for input circuit of junction type field effect transistor
Assignee: Iwatsu Electric Co Ltd
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Filing: 1970-03-09
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Granted: 1972-04-11
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Expires: 1990-03-09
Abstract
Abstract In a protective circuit for input circuit of a junction type field effect transistor, a plurality of gate electrodes are provided for the transistor, an input protective resistor is connected between a signal input terminal and an input side gate electrode and the other gate electrode is connected to the source electrode of the field effect transistor. The protective resistor functions to protect the field effect transistor against excessive forward voltage by passing current between the input side gate electrode and the source electrode and against excessive reverse voltage by passing current between the other gate electrode and the input side gate electrode.
Inventors
- 👤 Toru Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:35
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/20; H02H7/205
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A protective circuit for an input circuit of a junction type field effect transistor including at least first and second oppositely poled gate electrodes, a source electrode and a drain electrode, comprising an input protective resistor connected between a signal input terminal and said first gate electrode of said transistor, and means to connect said second gate electrode to have a predetermined potential relative to said source electrode, said protective resistor operative in combination only with the unidirectional conduction characteristics of said first and said second gate electrodes to protect said field effect transistor against excessive voltages in the forward direction by passing current between said first gate electrode and said source electrode and against excessive voltages in the reverse direction by passing current between said second gate electrode and said first gate electrode.
Claim 2
Dependent Claim
134 words
A protective circuit for an input circuit of a junction type field effect transistor including at least first and second oppositely poled gate electrodes, a source electrode and a drain electrode, comprising an input protective resistor connected between a signal input terminal and said first gate electrode of said transistor, and means to connect said second gate electrode to have a predetermined potential relative to said source electrode, said protective resistor operative in combination only with the unidirectional conduction characteristics of said first and said second gate electrodes to protect said field effect transistor against excessive voltages in the forward direction by passing current between said first gate electrode and said source electrode and against excessive voltages in the reverse direction by passing current between said second gate electrode and said first gate electrode.
Claim 3
Dependent Claim
34 words
The protective circuit according to claim 1 wherein said second gate electrode is connected to said source electrode through a bias resistor so as to be biased reversely with respect to said source electrode.
Claim 4
Dependent Claim
20 words
The protective circuit according to claim 1 wherein said junction type field effect transistor is of the N channel type.
Claim 5
Dependent Claim
20 words
The protective circuit according to claim 1 wherein said junction type field effect transistor is of the P channel type.
Claim 6
Dependent Claim
23 words
The protective circuit according to claim 1 wherein said second gate electrode is connected to have the same potential as said source electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |