STMicroelectronics Adds Controller for Computer and Consumer Disk Drives
STMicroelectronics today announced a new hard disk drive (HDD) motor-control chip that integrates all of the circuits required to drive both the spindle motor and the voice-coil of the drives used in personal computers. The L7207 HDD motor controller suits both the 5V drives made for mobile applications, and 12V desktop computer drives, thereby reducing inventory and manufacturing costs for manufacturers producing both types of drive while reducing component costs for others.
This new device can be used across a range of HDD specifications with the minimum of external components. Digital circuits, including ST's Smooth Drive® pseudo-sinusoidal digital-drive technique for minimizing acoustic noise from the spindle motor, are combined with high-efficiency power FETs and precision bipolar analog circuits on the same piece of silicon, using ST's proprietary BCD (BiPolar, CMOS, and DMOS) smart-power production technology. In addition to the Smooth Drive feature, the L7207 contains circuits to limit spindle current, sense start-up position and slow the spindle during power down.
The voice-coil section integrates power FETs and provides a class AB output stage with zero dead band and minimal crossover distortion. The voice-coil driver can operate in both linear and pulse-width modulation mode, allowing the drive to make significant power savings and extending battery life in portable applications. This area of the chip includes two 14-bit digital-to-analog converters for current commands, a sense-amplifier gain switch, and ramp load/unload circuits, plus a constant-voltage Retract function.
The L7207 is register controlled, and connects to the host system through a serial bus running at up to 40MHz. Its flexible digital architecture integrates all the functions needed in modern personal computer hard disk drives, and minimizes the number of additional components required for control circuits. Embedded auxiliary support functions for the drive include two externally adjustable linear regulators, two switching regulators (positive and negative), an internal isolation FET, monitoring of all voltage levels, a power-on reset circuit with integrated delay, shock-sensor circuit, and thermal sensing with over-temperature shutdown.
STMicroelectronics' product roadmap also includes a new motor controller for consumer electronics (CE) applications and is slated to be available for customer sampling in July 2006. This device is firmware compatible with the L7207 and is designed and specifically packaged in a small footprint package for the 1.8 inch and smaller drives widely used in compact CE products, such as portable music and video players. Quiet operation is especially important in these applications, and the device will include the Smooth Drive noise reducing drive system used in the L7207 as well as programmable linear and switching-voltage regulators. Motor peak current capability will be 0.5A, and the controller will offer a 50MHz serial interface.
The L7207 HDD motor controller is qualified for volume production, priced at $15.00 for large quantities, and is supplied in a compact eTQFP64 plastic package.
