Patent ID: 8351155
Filing Date: 2013-01-08
Classification: B82Y,G01R,G11B,H01F

Abstract:
1. A perpendicular magnetic recording disk drive: a disk having a perpendicular magnetic recording layer; a write head for magnetizing regions of the recording layer comprising a write driver capable of supplying write current in two directions to the main coil; a read head for detecting magnetized regions in the recording layer and generating a readback signal; a read amplifier for amplifying the readback signal from the read head; an integrated lead suspension (ILS) having electrically conductive traces connecting the write driver to the write head and electrically conductive traces connecting the read amplifier to the read head; STO control circuitry for supplying direct electrical current to the STO electrodes when write current is supplied to the main coil, the STO circuitry being connected to the STO via traces connecting the write driver to the write head; and a pair of matched resistors between the write driver and the write head; and wherein the STO control circuitry includes a low-pass filter coupled to the common-mode through the resistors, a voltage source, and a comparator for comparing the output of the low-pass filter to the voltage source.