Patent ID: 8217615

Claim:
A disk-drive spindle motor power regulator system comprising: a switching system comprising at least one power transistor for each of a plurality of phases of a disk-drive spindle motor; a switching controller configured to generate a plurality of switching signals configured to control the at least one power transistor for each of the plurality of phases of the disk-drive spindle motor; a current monitor configured to measure a magnitude of an individual phase current through at least one of the plurality of phases of the disk-drive spindle motor, wherein the current monitor includes at least one current sense system having: a first sense transistor configured to conduct a first reference current one of to and from a phase node associated with the respective one of the plurality of phases of the disk-drive spindle motor; a second sense transistor configured to conduct a second reference current one of to and from a power rail; and an operational amplifier configured to receive the first reference current, the second reference current, and a third reference current that flows one of to and from the phase node associated with the respective one of the plurality of phases of the disk-drive spindle motor and to generate a sense voltage that is substantially proportional to the individual phase current.