Patent US5280196A successfully refreshed from Google Patents.
US5280196A
Expired / Lapsed
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Magnetic head drive circuit
Assignee: Renesas Electronics Corp
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Filing: 1993-04-05
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Granted: 1994-01-18
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Expires: 2013-04-05
Abstract
Abstract A magnetic head drive circuit includes a first MOS transistor of a first conductivity type, a bipolar transistor of a second conductivity type, a second MOS transistor of the second conductivity type, a second bipolar transistor of the first conductivity type. The first MOS transistor of a first conductivity type has a source connected to a first power supply. The first bipolar transistor of a second conductivity type is connected in series with the first MOS transistor and has a common node thereof as a first output terminal, an emitter connected to a second power supply, and a collector current controlled as a constant current. The second MOS transistor of the second conductivity type has a source connected to the first power supply. The second bipolar transistor of the first conductivity type is connected in series with the second MOS transistor and has a common node thereof as a second output terminal, an emitter connected to the second power supply, and a collector current controlled as a constant current.
Inventors
- 👤 Eiji Shinozaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:39
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/567; G; G11; G11B; G11B5/00; G11B5/02; G11B5/09
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
157 words
A magnetic head drive circuit comprising: a first MOS transistor of a first conductivity type having a source connected to a first power supply; a first bipolar transistor of a second conductivity type connected in series with said first MOS transistor and having a common node thereof as a first output terminal, an emitter connected to a second power supply, and a collector current controlled as a constant current; a second MOS transistor of the first conductivity type having a source connected to said first power supply; a second bipolar transistor of the second conductivity type connected in series with said second MOS transistor and having a common node thereof as a second output terminal, an emitter connected to said second power supply, and a collector current controlled as a constant current; and a first constant current circuit connected between said second power supply and a common node between emitters of said first and second bipolar transistors.
Claim 2
Dependent Claim
157 words
A magnetic head drive circuit comprising: a first MOS transistor of a first conductivity type having a source connected to a first power supply; a first bipolar transistor of a second conductivity type connected in series with said first MOS transistor and having a common node thereof as a first output terminal, an emitter connected to a second power supply, and a collector current controlled as a constant current; a second MOS transistor of the first conductivity type having a source connected to said first power supply; a second bipolar transistor of the second conductivity type connected in series with said second MOS transistor and having a common node thereof as a second output terminal, an emitter connected to said second power supply, and a collector current controlled as a constant current; and a first constant current circuit connected between said second power supply and a common node between emitters of said first and second bipolar transistors.
Claim 3
Dependent Claim
63 words
A circuit according to claim 1, further comprising a magnetic head connected between said first and second output terminals, and wherein a pair of said first MOS transistor and said second bipolar transistor and a pair of said second MOS transistor and said first bipolar transistor are complementarily turned on and off to constitute a bridge circuit for supplying currents in both directions.
Claim 4
Dependent Claim
220 words
A magnetic head drive circuit comprising: a first MOS transistor of a first conductivity type having a source connected to a first power supply; a first bipolar transistor of a second conductivity type connected in series with said first MOS transistor and having a common node thereof as a first output terminal, an emitter connected to a second power supply, and a collector current controlled as a constant current; a second MOS transistor of the first conductivity type having a source connected to said first power supply; a second bipolar transistor of the second conductivity type connected in series with said second MOS transistor and having a common node thereof as a second output terminal, an emitter connected to said second power supply, and a collector current controlled as a constant current; and first switching means for selectively switching a base of said first bipolar transistor to an output of a reference current source or said second power supply, and second switching means for selectively switching a base of said second bipolar transistor to said output of said reference current source or the second constant current source, said first switching means constituting a second constant current source together with said first bipolar transistor, and said second switching means constituting a third constant current circuit together with said second bipolar transistor.
Claim 5
Dependent Claim
220 words
A magnetic head drive circuit comprising: a first MOS transistor of a first conductivity type having a source connected to a first power supply; a first bipolar transistor of a second conductivity type connected in series with said first MOS transistor and having a common node thereof as a first output terminal, an emitter connected to a second power supply, and a collector current controlled as a constant current; a second MOS transistor of the first conductivity type having a source connected to said first power supply; a second bipolar transistor of the second conductivity type connected in series with said second MOS transistor and having a common node thereof as a second output terminal, an emitter connected to said second power supply, and a collector current controlled as a constant current; and first switching means for selectively switching a base of said first bipolar transistor to an output of a reference current source or said second power supply, and second switching means for selectively switching a base of said second bipolar transistor to said output of said reference current source or the second constant current source, said first switching means constituting a second constant current source together with said first bipolar transistor, and said second switching means constituting a third constant current circuit together with said second bipolar transistor.
Claim 6
Dependent Claim
118 words
A circuit according to claim 3, wherein said first switching means comprises a third MOS transistor of the first conductivity type connected between said base of said first bipolar transistor and said output of said reference current source and a fourth MOS transistor of the second conductivity type connected between said base of said first bipolar transistor and said second power supply, and said second switching means comprises a fifth MOS transistor of the first conductivity type connected between said base of said second bipolar transistor and said output of said reference current source and a sixth MOS transistor of the second conductivity type connected between said base of said second bipolar transistor and said second power supply.
Claim 7
Dependent Claim
63 words
A circuit according to claim 3, further comprising a magnetic head connected between said first and second output terminals, and wherein a pair of said first MOS transistor and said second bipolar transistor and a pair of said second MOS transistor and said first bipolar transistor are complementarily turned on and off to constitute a bridge circuit for supplying currents in both directions.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1997-01-17 | 1997-07-19 | 1998-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-17 | 2001-07-19 | 2002-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-17 | 2005-07-19 | 2006-01-18 | $7700.00 | Window Closed / Lapsed |