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:
Feb. 09, 2010
Filed:
Jan. 11, 2005
James Patrick Howley, Broomfield, CO (US);
Michael Philip Straub, Longmont, CO (US);
James Patrick Howley, Broomfield, CO (US);
Michael Philip Straub, Longmont, CO (US);
Agere Systems Inc., Allentown, PA (US);
Abstract
A hard disk drive write driver circuit is described that can change the output impedance of the write driver by use of a lookup table of control values. A control value is selected from the lookup table by using an address based on a dynamic system variable and a program controlled value. The dynamic system variable is converted to a digital representation. The digital representation and a portion of the program controlled value are used as an address to the lookup table to select a control value. The write driver is responsive to the selected control value to control overshoot current. A method to digitally program the output impedance of a preamp write driver based on realistic operating data is also discussed. An additional approach to controlling overshoot current in a write driver through digital control of overshoot duration is also described.