Patent ID: 6246269
Filing Date: 2001-06-12
Classification: G11B,H03K

Abstract:
A write driver circuit for a disk drive comprising an H-switch having first and second nodes for connection to an inductive write head, first and second switches operable to direct write current from a current source in a first direction through the write head when the H-switch is operating in a first mode, and in a second direction, opposite the first direction, through the write head when the H-switch is operated in a second mode, the H-switch being operable such that a value of a first voltage at the first node and a value of a second voltage at the second node is greater than a first threshold voltage value when the write current flows in a quiescent condition through the write head, the H-switch being operable to cause one of the first and second voltages at one of the first and second nodes to drop to below the first threshold voltage value upon a change between the first and second modes of operation, the improvement comprising:first programmable current source connected to the first and second nodes and responsive to a drop in the one of the first and second voltages at the one of the first and second nodes below the first threshold voltage value for injecting an overshoot compensation current into the one of the first and second nodes.