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:
Mar. 05, 2002
Filed:
Apr. 11, 2001
Edward N. Jeffrey, Garland, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A circuit ( ) and method for applying drive voltages to a voice coil motor (VCM) ( ) of a mass data storage device ( ) has two driver sets, each having a high side driver (HSD) ( ) and a low side driver (LSD) ( ) connected to the VCM ( ). Each driver set has two SENSEFETs ( ), each having a power FET and a sense FET. A circuit ( ) is provided for sensing a sense current in the sense FET of the LSD, and a circuit ( ) is provided for increasing the bias on the gates of the SENSEFET ( ) in the LSD when the sense current falls below a predetermined level (VREF). Also, a circuit ( ) is provided for driving a predetermined current in the SENSEFET of the HSD when the sense current falls below the predetermined level. Thus, a current at the predetermined level always flows in the SENSEFETs ( ).