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Fujitsu MHV2080AH Actuator motor control, Operation to move the head to the reference cylinder

Models: MHV2040AH MHV2080AH MHV2060AH MHV2100AH

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Theory of Device Operation

4.7.4 Actuator motor control

The voice coil motor (VCM) is controlled by feeding back the servo data recorded on the data surface. The MPU fetches the position sense data on the servo frame at a constant interval of sampling time, executes calculation, and updates the VCM drive current.

The servo control of the actuator includes the operation to move the head to the reference cylinder, the seek operation to move the head to the target cylinder to read or write data, and the track-following operation to position the head onto the target track.

(1) Operation to move the head to the reference cylinder

The MPU moves the head to the reference cylinder when the power is turned. The reference cylinder is in the data area.

When power is applied the heads are moved from the outside of media to the normal servo data zone in the following sequence:

a)Micro current is fed to the VCM to press the head against the outer direction.

b)The head is loaded on the disk.

c)When the servo mark is detected the head is moved slowly toward the inner circumference at a constant speed.

d)If the head is stopped at the reference cylinder from there. Track following control starts.

(2) Seek operation

Upon a data read/write request from the host, the MPU confirms the necessity of access to the disk. If a read/write instruction is issued, the MPU seeks the desired track.

The MPU feeds the VCM current via the D/A converter and power amplifier to move the head. The MPU calculates the difference (speed error) between the specified target position and the current position for each sampling timing during head moving. The MPU then feeds the VCM drive current by setting the calculated result into the D/A converter. The calculation is digitally executed by the firmware. When the head arrives at the target cylinder, the track is followed.

(3) Track following operation

Except during head movement to the reference cylinder and seek operation under the spindle rotates in steady speed, the MPU does track following control. To position the head at the center of a track, the DSP drives the VCM by feeding micro current. For each sampling time, the VCM drive current is determined by filtering the position difference between the target position and the position clarified by the detected position sense data. The filtering includes servo compensation. These are digitally controlled by the firmware.

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Fujitsu MHV2080AH, MHV2100AH Actuator motor control, Operation to move the head to the reference cylinder, Seek operation
Page 73 Page 75

MHV2040AH, MHV2080AH, MHV2060AH, MHV2100AH specifications

The Fujitsu MHV series of hard disk drives, specifically the MHV2060AH, MHV2080AH, MHV2100AH, and MHV2040AH, are renowned for their reliability and performance in the mobile HDD segment. Designed primarily for use in laptops and other portable devices, these drives integrate cutting-edge technologies to meet the demands of today's data-intensive applications.

One of the hallmark features of the MHV series is its high data density, allowing for substantial storage capabilities in compact sizes. The MHV2060AH offers a storage capacity of 60 GB, while the MHV2080AH and MHV2100AH offer 80 GB and 100 GB respectively. The MHV2040AH provides a slightly more modest but still robust 40 GB of storage. This range of capacities ensures that users can select the model that best fits their storage needs.

The drives utilize the latest perpendicular magnetic recording (PMR) technology, which enhances recording efficiency and increases data storage densities. This technology significantly optimizes the use of disk surface area, providing better performance and more reliable data access. Additionally, the MHV series incorporates an advanced actuator system that ensures precision head positioning, enhancing data integrity and reducing error rates during read and write operations.

In terms of performance, the MHV series maintains a revolutions per minute (RPM) rating of 5400, which strikes a balance between speed and energy efficiency, making these drives suitable for low-power applications. The drives are also designed with a low acoustic level, generating minimal noise during operation—a crucial factor for mobile users who prefer quieter devices.

Furthermore, the Fujitsu MHV series features a robust shock resistance design, allowing them to withstand the rigors of mobile computing. This makes them suitable for use in portable environments subject to vibration and physical movement, thus ensuring data security and drive longevity.

Overall, the Fujitsu MHV2060AH, MHV2080AH, MHV2100AH, and MHV2040AH represent a formidable selection of mobile hard disk drives filled with advanced technologies and features, making them well-suited for a wide range of applications in today's fast-paced digital world. With their combination of storage capacity, performance, and durability, these drives continue to serve as reliable solutions for users seeking efficient data storage in portable formats.