| 摘要 |
A system for providing feedback to a selected read head in a multi-head disk drive includes first and second feedback circuits is disclosed. A first feedback circuit 200 provides for correction of the output of the selected read head during normal operation. The first feedback circuit 200 produces a differential output current proportional to an offset voltage detected on the read head output nodes 103 and 104. This differential output current charges external capacitor 190. The voltage across capacitor 190 is supplied to voltage inputs of the selected read head as a feedback voltage. When the feedback voltage reaches the desired level, nodes 103 and is 104 equalize, as do the output currents of the first feedback circuit 200. The second feedback circuit 300 provides for quick recovery of the system after a change in read heads. The second feedback circuit 300 provides an amplified output current to capacitor 190, causing capacitor 190 to adjust to the desired charge level more quickly than it would if only the first feedback circuit 200 were in operation.
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