L6243DS

VOICE COIL MOTOR DRIVER

5-12V OPERATION

PARKING

FUNCTION

FOR

HARD

DISK

HEAD ACTUATOR

OUTPUT CURRENT UP TO 1A DC, 1.2A

PEAK

LOW SATURATION VOLTAGE

LOGIC AND POWER SUPPLY MONITOR

LINEAR CONTROL

THERMAL PROTECTION

ENABLE FUNCTION

CURRENT

SENSE

RESISTOR CONNEC-

TIONS

DESCRIPTION

The L6243DS is a Bipolar IC developed for use in

Mass Storage Head Actuator positioning applica-

tions. The Power Op-Amp Output Bridge, Differ-

ential

Amplifier, and Error Amplifier, are control-

led by TTL/CMOS, input compatible, Digital Logic,

and an Analog Current Control Voltage.

A simple

RC compensation network, tied to the

output of the Error Amp, will configure the system

to work as a Transconductance Amplifier to drive

a Voice Coil Motor in Linear Mode.

Additional features include Power On Reset De-

lay, Enable and Park. A logic low at the Park input

activates the parking function. Holding the Enable

input low will disable the device by forcing the

outputs into a tristate mode. Power Fail Monitors

for the logic and power supplies initiate an auto-

matic parking sequence during a power failure. A

resistor programmed parking voltage enables a

constant velocity head retract.

February 1998

BRIDGE

POWER

STAGE

PARK

VOLTAGE

GENERATOR

-

+

-

+

-

+

INTERNAL

VOLTAGE

REFERENCE

-

+

THERMAL

PROTECTION

FALL TIME

DELAY

POWER FAIL

THRESHOLD

(12V)

PARK VOLTAGE

PROGRAM

PARK POWER

OUT A

OUT B

SENSE IN B

SENSE IN A

SENSE OUT

ERROR IN

ERROR OUT

R2

R1

Cf

Rf

Rsense

VOICE COIL

SNUBBER

VREF

PARK

POR

VCC SENSE OUT

POR DELAY

LOGIC SUPPLY FILTER

D96IN469

VDD B

VDD A

GND

ENABLE

LOGIC

SUPPLY

SENSE

BLOCK DIAGRAM

SO24

ORDERING NUMBER: L6243DS

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