Lexington, Mass.—STMicroelectronics' motor control chip integrates all of the circuitry required to drive both the spindle motor and the voice-coil of a personal computer's hard disk drive (HDD). It suits both the 5-volt drives for mobile applications and 12-volt desktop computer drives, thereby reducing inventory and manufacturing costs.
This bipolar-CMOS-DMOS (BCD) chip employs the company's Smooth Drive pseudo-sinusoidal digital-drive technique for minimizing acoustic noise from the spindle motor; precision bipolar analog circuits; and high-efficiency power FETs. In addition to the Smooth Drive feature, the L7207 has circuitry to limit spindle current, sense start-up position, and slow the spindle during power down.
The voice-coil section integrates power FETs in class AB operation with zero dead-band and has minimal crossover distortion. The voice-coil driver can operate in both the linear and PWM modes to extend battery life in portable applications. The voice-coil section includes two 14-bit D/A converters for current commands, a sense-amplifier gain switch, ramp load/unload circuits, and a constant-voltage Retract function.
Embedded auxiliary support circuitry for the drive includes two externally adjustable linear regulators, two switching regulators (positive and negative),
an internal isolation FET, a monitor to check on all voltage levels, a power-on reset (POR) circuit with integrated delay, a shock-sensor circuit, and thermal sensing circuit with over-temperature shutdown.
The company's product roadmap also includes a motor controller for consumer electronics (CE) applications and is slated for customer sampling in July. This device is firmware compatible with the L7207 and is designed and packaged in a small footprint for the 1.8-inch and smaller drives widely used in compact CE products such as portable music and video players. The device includes the Smooth Drive noise reducing drive system used in the L7207 as well as programmable linear and switching-voltage regulators. Motor peak-current capability is 500 mA, and the controller offers a 50 MHz serial interface.
The L7207's product datasheet will be available shortly on the company website. The chip, in a eTQFP64 plastic package, is qualified for volume production, and is priced at $15 each in large quantities.
STMicroelectronics, 1-781-861-2650, www.st.com