Product category:
Power Supply ICs and Controllers
News Release from: STMicroelectronics | Subject: L7220
Edited by the Electronicstalk Editorial
Team on 22 January 2008
Motor controller takes charge of HDDs
Controller integrates all circuits required to drive both spindle and voice-coil motors, plus the motor drive power FETs and multiple high-efficiency voltage regulators.
STMicroelectronics has developed a hard-disk drive (HDD) motor-control chip intended for demanding enterprise-level HDD applications The new L7220 controller integrates all of the circuits required to drive both the spindle motor and the voice-coil motor (VCM), plus the motor drive power FETs and multiple high-efficiency voltage regulators
This article was originally published on Electronicstalk on 8 Nov 2004 at 8.00am (UK)
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It continues and complements ST's HDD controller family, which includes the L7207 HDD controller for mobile and desktop drives.
ST is the market leader in enterprise HDD controllers.
No other manufacturer offers such a high level of integration, enabling drive manufacturers to significantly reduce their bill of materials (BOM) and save space within the drive.
Enterprise HDDs - typically used in server farms, workstations and high-performance desktop systems - are moving to small form factor (SFF) sises, where achieving a smaller PCB footprint is critical; the integration in the L7220 of the power FETs for both spindle and voice coil motors is a major contribution.
The new controller embeds four highly efficient hysteretic positive switching regulators, and one -5V regulator, all with voltage margining.
As well as eliminating the need for external regulators for the various voltages required by the drive, hysteretic control provides fast transient response and very high efficiency, increasingly important in server farms in particular, where reducing power consumption is a principal requirement.
In addition, the L7220 contains the latest version of ST's respected Smooth Drive pseudosinusoidal digital-drive technique for minimising acoustic noise from the spindle motor, plus other circuits to limit spindle current, sense the startup position and slow the spindle during power down.
The spindle-motor section power FETs are capable of delivering 3.0A peak current; maximum on-resistance is 0.3ohm at 125C.
The VCM driver has 2.5A capability and 0.3ohm maximum bridge impedance.
It includes circuitry for discontinuous mode ramp unload at power off, with end of travel detection; an alternative voltage-mode power-off scheme; and a 15bit linear DAC with gain switch, for current commands.
Evaluation samples of the L7220 are available now, and volume production in planned for mid-2008.
The controller is priced at US $15.00, in a 64-pin 10 x 10 x 1mm ePad package.
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