L6243DS Datasheet, PDF (1/8 Pages) STMicroelectronics – VOICE COIL MOTOR DRIVER

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
BLOCK DIAGRAM
SO24
ORDERING NUMBER: L6243DS
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.
OUT A
SNUBBER
VOICE COIL
Rsense
OUT B
SENSE IN B SENSE IN A
V_IN
Cf
R1
R2
Rf
SENSE OUT ERROR IN
ERROR OUT
GND
VDD A
VDD B
PARK POWER
PARK VOLTAGE
PROGRAM
POWER FAIL
THRESHOLD
(12V)
LOGIC
SUPPLY
SENSE
LOGIC SUPPLY FILTER
-
+
BRIDGE
POWER
STAGE
PARK
VOLTAGE
GENERATOR
V_CC
-
+
+
-
-
+
INTERNAL
VOLTAGE
REFERENCE
VCC SENSE OUT ^{POR DELAY}
POR
-
+
VREF
THERMAL
PROTECTION
PARK
ENABLE
FALL TIME
DELAY
D96IN469
February 1998
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