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. 15, 2006
Filed:
Jun. 30, 2004
Alaa Y. El-sherif, Plano, TX (US);
Eugene F. Plutowski, Rochester, MN (US);
Kevin W. Ziemer, Plano, TX (US);
Alaa Y. El-Sherif, Plano, TX (US);
Eugene F. Plutowski, Rochester, MN (US);
Kevin W. Ziemer, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A positioning driver () for a voice coil motor () in a disk drive system () is disclosed. Pulse-width-modulated prestage drivers () are coupled to power transistors () arranged in an 'H' bridge for driving the voice coil motor (), biased with a power supply voltage (V). The pulse-width-modulated prestage drivers () drive the power transistors () according to a comparison between an error signal from an error amplifier () and a ramp clock signal (RMP) generated by a ramp clock generator (). The ramp clock generator () includes a control circuit () that modulates the high and low limits of the ramp clock signal (RMP) in response to variations in the power supply voltage (V). This modulation of the high and low limits compensates for variations in the gain of the power transistors () resulting from variations in the power supply voltage (V). The control circuit () may also modulate the slope of the ramp clock signal (RMP) according to variations in the power supply voltage (V), for example to maintain a constant frequency.