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. 11, 2002
Filed:
Oct. 27, 2000
Indumini Ranmuthu, Plano, TX (US);
Davy H Choi, Garland, TX (US);
Sami Kiriaki, Plano, TX (US);
Yong Han, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Preamplifiers are used in hard disk drive applications to read data stored on magnetic disk. Current bias current sense preamplifiers have a problem with bandwidth rolloff due to relatively high inductance. Voltage sense preamplifiers have a problem with peaking due to input capacitance. An improved current bias voltage sense preamplifier inserts a PMOS transistor M between the Rmr head and the bipolar transistor Q . The PMOS transistor M and the bipolar transistor Q form a high impedance voltage sense preamplifier. Biasing of the MR head is performed transistors M and M that mirror the current supplied by the current digital to analog converter into the MR head. Hence, the preamplifier is also of the current bias type. Peaking is controlled through a programmable current in an input capacitance cancellation circuit