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US 7,623,316 B1Granted
Circuit and method for protecting emergency head-retract capacitor in a hard disk drive
AssigneeMarvell International Ltd.
InventorsSakti Rana, Yayue Zhang, Siew Yong Chui
Life of this patent
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Abstract
A charging system includes a current source, a voltage pump, and a comparator that compares a charging level of a capacitor to each of a first threshold and a second threshold. A controller turns on the voltage pump and turns off the current source after the charging level exceeds the first threshold, and turns off the voltage pump and turns on the current source when the charging level falls below the second threshold. The first threshold is greater than the second threshold.
Claims15
A charging system comprising:
- a current source;
- a voltage pump;
- a comparator that compares a charging level of a capacitor to each of a first threshold and a second threshold;
- and
- a controller that turns on the voltage pump and turns off the current source after the charging level exceeds the first threshold, and that turns off the voltage pump and turns on the current source when the charging level falls below the second threshold,
- wherein the first threshold is greater than the second threshold.
3 more elements
A disk drive system comprising:
- a drive head assembly;
- a capacitor;
- a charging system comprising:
- a current source that charges the capacitor;
- a voltage pump that charges the capacitor;
- a comparator that compares a charging voltage of the capacitor to each of a first threshold and a second voltage threshold;
- and
- a controller that turns on the voltage pump and turns off the current source after the charging voltage exceeds the first voltage threshold, and that turns off the voltage pump and turns on the current source when the charging voltage falls below the second voltage threshold, wherein the first voltage threshold is different than the second voltage threshold;
- and
- a driver circuit that communicates with the capacitor and that retracts the drive head assembly using power stored by the capacitor when the disk drive system loses power.
7 more elements
Dependencies are inferred from the claim text.