The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 20, 1995
Filed:
Jan. 21, 1994
Robert F Smith, San Jose, CA (US);
Seagate Technology, Inc., Scotts Valley, CA (US);
Abstract
A preamplifier configured for connection to a magnetoresistive transducer makes use of a first and second transistor connected in a common emitter differential pair configuration. The differential pair configuration has a pair of input terminals and a pair of output terminals. A first feedback circuit is included for providing feedback to at least one of a pair input terminals based on selected relatively slowly changing voltages between a pair of preamplifier output terminals. In this manner, the first feedback circuit minimizes differential voltages at the preamplifier output terminals. A second feedback circuit is provided for supplying feedback to at least one of the preamplifier input terminals based on relatively low frequency voltage magnitudes at one of the pair of input terminals. In this manner, a selected common mode voltage magnitude is maintained at one of the pair of input terminals.