US3763383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drive circuit for inductive device
Assignee: International Business Machines Corp
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Filing: 1972-08-21
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Granted: 1973-10-02
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Expires: 1992-08-21
Abstract
Abstract A drive circuit has two circuit paths, each path including an inductive coil means to which a constant current source is applied; and a switching element that clamps the coil means to a fixed voltage.
Inventors
- 👤 H Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:29
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/022; H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/64; H03K17/66; H03K17/661
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
A current switching circuit comprising: an inductive coil means, one end of said coil means connected to one branch of said circuit, and the other end of said coil means connected to a second branch of said circuit, said branches having substantially the same configuration; a first current source means for providing a constant current coupled to said coil means; first and second switching elements respectively connected in each branch to said coil means; a source of reference potential; means for coupling said switching elements to said source of reference potential; second current source means coupled between Said switching elements for providing a constant current of greater magnitude than said first constant current source means; and means for activating said switching elements in alternation to develop current flow alternately in said circuit branches.
Claim 2
Dependent Claim
133 words
A current switching circuit comprising: an inductive coil means, one end of said coil means connected to one branch of said circuit, and the other end of said coil means connected to a second branch of said circuit, said branches having substantially the same configuration; a first current source means for providing a constant current coupled to said coil means; first and second switching elements respectively connected in each branch to said coil means; a source of reference potential; means for coupling said switching elements to said source of reference potential; second current source means coupled between Said switching elements for providing a constant current of greater magnitude than said first constant current source means; and means for activating said switching elements in alternation to develop current flow alternately in said circuit branches.
Claim 3
Dependent Claim
29 words
A switching circuit as in claim 1, wherein said inductive coil means comprises a center-tapped coil, said first current source being applied to the center tap of said coil.
Claim 4
Dependent Claim
31 words
A switching circuit as in claim 1, wherein said switching elements are transistors; and said activating means comprises logic trigger signal means that are applied to the bases of said transistors.
Claim 5
Dependent Claim
30 words
A switching circuit as in claim 3, including unilateral conducting devices coupled between said transistors, so that when current flows in one circuit branch, the other circuit branch is non-conductive.
Claim 6
Dependent Claim
15 words
A switching circuit as in claim 4, wherein said unilateral conducting devices are clamping diodes.
Claim 7
Dependent Claim
38 words
A switching circuit as in claim 3, wherein the collector electrodes of said transistors are connected to the ends of said coil means, and the emitter electrodes of said transistors are connected to said second constant current source.
Claim 8
Dependent Claim
24 words
A switching circuit as in claim 1, including a damping resistance means coupled between said first constant current source and a reference voltage means.
Claim 9
Dependent Claim
36 words
A switching circuit as in claim 1, wherein said coil means comprises a single coil, and said first constant current source means comprises separate current sources that are applied respectively to the ends of said coil.
Claim 10
Dependent Claim
20 words
A switching circuit as in claim 1, wherein said coil means is part of a magnetic head write driver circuit.
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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) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |