Western Digital Corporation

Kenneth D Donner

Marc B Goldstone

Dung T Nguyen

David E McKinley

Ralph A Proud

Rudolf Wiegand

Donn A Hopkins

A disk drive circuit that includes a configuration resistor, a reference resistor, a capacitor and a processor. The processor is mounted on a first circuit assembly in the disk drive, such as the controller circuit board, and the configuration resistor is mounted on a second circuit assembly, such as the head-disk assembly (I-IDA). The resistance of the configuration resistor corresponds to the configuration of the second circuit assembly. The configuration may represent the number of heads or the type of preamplifier in the IDA. The processor calculates the resistance of the configuration resistor to determine the configuration of the second circuit assembly in the following manner. The processor charges the capacitor. The processor then allows the capacitor to discharge through a first circuit that includes both the configuration resistor and the reference resistor and measures the discharge time or time constant. The processor again charges the capacitor. The processor then allows the capacitor to discharge through a second circuit that includes the configuration resistor but not the reference and measures the time constant. The processor calculates the resistance of the configuration resistor in response to the ratio of the time constants of the first and second circuits.

Analog-to-digital converter for configuration control

A method for controlling a rotating disk magnetic data storage device employing several reduced power modes which are automatically entered and exited under the control of the rotating disk device microcontroller. Two modes are provided which are fully responsive to host computer commands, and are thereby transparent to the host computer user, all providing significant power savings. An additional full power down mode is provided which can be initiated by a command from the host computer user, wherein the operational state parameters of the rotating disk device are stored in the host computer until the host computer powers on the device. At this time the stored state parameter are restored into the rotating disk device allowing it to resume its operational state immediately prior to the power suspension. Additionally, a reduced power startup procedure is provided where a low current start is first attempted, which will be successful in a high percentage of attempts, followed by a higher current attempt if the first attempt is unsuccessful. A portion of the drive circuitry is disabled during the startup procedure to further save energy.

Disk drive with reduced power modes

Growing community of inventors

Laguna Niguel, CA, United States of America

Kenneth D Donner