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:
Aug. 06, 2002
Filed:
Apr. 15, 1999
Scott J. Tucker, Raleigh, NC (US);
Wei Hong, Durham, NC (US);
Mitsubishi Electric and Electronics U.S.A., Inc., Durham, NC (US);
Abstract
An arrangement for reading data from a magnetic data carrier using a magneto-resistive (MR) head. A bias current source supplies the MR head with a bias current adjustable after MR head change. A bias current control signal having multiple control bits is used for adjusting the bias current. A noise shunting capacitor is connected to the MR head for reducing noise caused by the bias current. A discharging circuit is coupled to the noise shunting capacitor to discharge the capacitor when the bias current is being adjusted, in order to reduce bias current settling time. The discharging circuit comprises a pair of switches for each control bit of the bias current control signal. One of the switches is connected to a positive plate of the noise shunting capacitor, and another switch is coupled to a negative plate of the capacitor. The switches are controlled by a one-shot multivibrator triggered by a falling edge of the corresponding control bit. Weighting resistors are connected to each switch for weighting a discharge current produced by the switch in accordance with a position of the corresponding control bit so as to produce a larger discharge current in response to a higher-order control bit of the bias current control signal.