Write-to read switching improvement for differential preamplifier circuits in hard disk drive systems

摘要

The present invention relates to a preamplifier circuit (150) comprising a plurality of amplifier stages (102,104,106,108) coupled together and operable to consecutively amplify a signal associated with a head of a hard disk drive. The preamplifier circuit further comprises a power delivery circuit operably coupled to the amplifier stages and operable to provide power (VDD,VSS) to the amplifier stages in a substantially concurrent manner when the hard disk drive is transitioning from a write state to a read state (WR†’RD). In addition, the circuit comprises a control circuit (152) operably coupled to the amplifier stages, and operable to activate at least two of the plurality of amplifier stages in a generally consecutive manner after the providing of power to the amplifier stages. In the above manner a saturation of an output of the preamplifier circuit is avoided by preventing substantially a propagation of glitches through the preamplifier circuit and providing for a substantially fast write-to-read transition time.