L6245

5V HARD DISK DRIVE POWER COMBO

PRODUCT PREVIEW

General

+5V OPERATION

REGISTER BASED ARCHITECTURE

MINIMUM EXTERNAL COMPONENTS

SLEEP

AND

IDLE

MODES

FOR

LOW

POWER CONSUMPTION

SELECTABLE GAINS FOR BOTH VCM AND

SPINDLE Gm LOOP

LINEAR CURRENT CONTROL LOOPS FOR

BOTH VCM AND SPINDLE

8 BIT D/A FOR ACTUATOR DRIVER AND

SPINDLE DRIVER

VCM Driver

CURRENT SENSE CONTROL (VOLTAGE

PROPORTIONAL TO CURRENT)

VOLTAGE SENSE CONTROL

(VOLTAGE

PROPORTIONAL

TO

THE

VOLTAGE

ACROSS THE VCM)

TWO CURRENT RANGES FOR SEEKING

AND TRACKING

INTERNAL REGISTER FOR POWER AMP

CONTROL LINES

SPEED

OUTPUT

(VOLTAGE

PROPOR-

TIONAL TO BEMF)

Spindle Driver

BEMF PROCESSING FOR SENSORLESS

MOTOR COMMUTATION

PROGRAMMABLE COMMUTATION PHASE

DELAY

PROGRAMMABLE SLEW-RATE FOR RE-

DUCED EMI

0.7

Ω TYP. FOR ANY HALF BRIDGE

CROSS CONDUCTION PROTECTION

SYNTHESIZED HALL OUTPUT

Other Functions

POWER UP SEQUENCING

POWER DOWN SEQUENCING

LOW VOLTAGE SENSE

ACTUATOR RETRACTION

DYNAMIC BRAKE

THERMAL SHUTDOWN

DESCRIPTION

The L6245 contains in a single chip all the func-

tions to operate a sensorless brushless (DC) mo-

tor and a voice coil motor, suitable for hard disk

drive applications.

The device is configured to interface directly to

an 8 bit parallel microprocessor bus, and has a

register based architecture to reduce number of

interconnection lines. All the positioning loop for

sensorless spindle is integrated, including BEMF

sensing, digital masking, digital delay and se-

quencing. All timing function are performed digi-

tally, thus no external filtering components are re-

quired.

The VCM driver is a transconductance amplifier,

able to provide 2 different current ranges, suitable

for seeking or tracking of the head actuator.

When a low voltage is detected, a monitor, in se-

quence, resets the internal registers, puts in tris-

tate the spindle powers, retracts the actuator, and

applies the dynamic brake of the spindle.

The L6245 is realized in Multipower-BCD 2 tech-

nology, which combine isolate DMOS power tran-

sistors with CMOS and

Bipolar circuits in the

same monolithic layer, and is assembled in a 64-

pin PQFP.

This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

October 1992

PQFP64

ORDERING NUMBER: L6245

MULTIPOWER BCD TECHNOLOGY

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