Patent ID: 8134318
Filing Date: 2012-03-13
Classification: G11B

Abstract:
1. A system for performing retract of a voice coil motor (VCM), the system comprising: drive circuitry coupled to drive the VCM according to an operating logic state of the system; current shaping circuitry that includes a switch coupled in parallel with a current shaping resistor, and wherein the current shaping circuitry, wherein the current shaping circuitry is configured to temporarily decrease bandwidth of a VCM transconductance loop in response to a control signal, and wherein the VCM transconductance loop including at least the VCM, and wherein the current shaping circuitry and the drive circuitry, and wherein the switch being operated in response to the control signal to modify the bandwidth of the VCM transconductance loop; and logic configured to provide the control signal at an end portion a drive logic state to enter a current shaping logic state as a transition from the drive logic state to a floating logic state to reduce current through the VCM such that acoustic emissions from the VCM are mitigated during the retract.