Patent ID: 9099944
Filing Date: 2015-08-04
Classification: G11B,H02P

Abstract:
1. A disk drive comprising: A. a spindle motor; B. spindle motor transistor circuitry coupled to the spindle motor; C. spindle motor driver circuitry selectively coupled to the spindle motor transistor circuitry; D. spindle motor return driver circuitry selectively coupled to the spindle motor transistor circuitry; E. a spindle switch selectively coupling one of the spindle motor driver circuitry and the spindle motor return driver circuitry to the spindle motor transistor circuitry; F. a voice coil motor; G. voice coil motor transistor circuitry coupled to the voice coil motor; H. voice coil motor driver circuitry selectively coupled to the voice coil motor transistor circuitry; I. voice coil motor return driver circuitry selectively coupled to the voice coil motor transistor circuitry; J. a voice coil switch selectively coupling one of the voice coil motor driver circuitry and the voice coil motor return driver circuitry to the voice coil motor transistor circuitry; and K. return control circuitry coupled to the spindle motor return driver circuitry and to the voice coil motor return driver circuitry, the return control circuitry including a voice coil motor back EMF analog to digital converter coupled to the voice coil motor and having a digital output, and including refraction control circuitry having an input connected to the digital output and having outputs coupled to the voice coil motor transistor circuitry.