Patent ID: 7705548

Claim:
A method of enhancing the efficiency of energy recovery in charging a hold capacitor coupled between power supply nodes of output MOS transistor bridge stages driving a multiphase spindle motor and a voice coil motor of a disk storage device, the method comprising: in case of failure of an external power supply of the device, and in order to allow the voice coil motor to complete an emergency ramp loading of a head carrying arm, rectifying currents produced by back electromotive forces in the phase windings of the spindle motor and forcing a rectified charge current through the hold capacitor by switching the MOS transistors of the output half-bridge stages from a braking configuration, wherein either the high-side transistors or the low-side transistors of the half bridges are turned on, to an active step-up current circulation configuration with the transistors of the half bridges being selectively turned on or off in a way such as to circulate the currents of the phase windings of the spindle motor, through selectively turned on transistors of the respective half bridges for charging the hold capacitor.