Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of biasing or erasing
Reexamination Certificate
2007-10-19
2010-02-02
Tzeng, Fred (Department: 2627)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of biasing or erasing
Reexamination Certificate
active
07656601
ABSTRACT:
A circuit for measuring resistance of a magnetoresistive head. First and second current biasing circuits are respectively coupled to opposite sides of the head. The first biasing circuit includes a first resistance, and the second biasing circuit includes a second resistance. First and second current mirrors are respectively coupled to the first and second biasing circuits. A current leg is coupled to the current mirrors. The current mirrors drive current in the resistances so that a first voltage across the first resistance is substantially equal and opposite to a second voltage across the second resistance. The biasing circuits bias current through the head such that a voltage on the first side of the head is close to the first voltage and a voltage on the second side of the head is close to the second voltage, so that the common mode voltage of the head will be close to zero.
REFERENCES:
patent: 4853633 (1989-08-01), Matsumoto
patent: 5313342 (1994-05-01), Soda et al.
patent: 5534818 (1996-07-01), Peterson
patent: 5712739 (1998-01-01), Nakamura et al.
patent: 5856891 (1999-01-01), Ngo
patent: 5886568 (1999-03-01), Ngo et al.
patent: 5986839 (1999-11-01), Klaassen et al.
patent: 6023395 (2000-02-01), Dill et al.
patent: 6101056 (2000-08-01), Klaassen et al.
patent: 6128149 (2000-10-01), Li
patent: 6225802 (2001-05-01), Ramalho et al.
patent: 6404579 (2002-06-01), Ranmuthu et al.
patent: 6490112 (2002-12-01), Ranmuthu et al.
patent: 7027271 (2006-04-01), Inage et al.
patent: 2002/0036874 (2002-03-01), Inage et al.
patent: 2006/0152838 (2006-07-01), Fitzgerald et al.
patent: 2007/0070536 (2007-03-01), Christianson et al.
patent: 2008/0062551 (2008-03-01), Dolan et al.
K. Jensen, “Cause and Effects of Common-Mode Leakthrough”, Quantum Design, Technical Bulletin. (copy right, 1999).
“Common-Mode Noise: Sources and Solutions”, Agilent Technologies, Application Note 1043, 1999.
Marvell International Ltd.
Tzeng Fred
LandOfFree
Current biasing circuit to reduce MR common mode voltage... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Current biasing circuit to reduce MR common mode voltage..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Current biasing circuit to reduce MR common mode voltage... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-4233494