L6243DS [STMICROELECTRONICS]
VOICE COIL MOTOR DRIVER; 音圈电机驱动器
| 型号： | L6243DS |
| 厂家： | 
ST |
| 描述： | VOICE COIL MOTOR DRIVER |
| 文件： | 总8页 (文件大小：93K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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
SO24
THERMAL PROTECTION
ENABLE FUNCTION
ORDERING NUMBER:
L6243DS
CURRENT SENSE RESISTOR CONNEC-
TIONS
to work as a Transconductance Amplifier to drive
a Voice Coil Motor in Linear Mode.
DESCRIPTION
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.
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
SNUBBER
VIN
Cf
R1
R2
VOICE COIL
Rsense
Rf
OUT A
OUT B
SENSE IN B
SENSE IN A
SENSE OUT
ERROR IN
ERROR OUT
-
-
GND
+
+
BRIDGE
POWER
STAGE
VDD A
VDD B
VREF
PARK POWER
PARK
VOLTAGE
GENERATOR
PARK VOLTAGE
PROGRAM
THERMAL
PROTECTION
VCC
POWER FAIL
THRESHOLD
(12V)
-
+
PARK
+
-
LOGIC
SUPPLY
SENSE
ENABLE
-
+
INTERNAL
VOLTAGE
REFERENCE
FALL TIME
DELAY
LOGIC SUPPLY FILTER
POR DELAY
D96IN469
VCC SENSE OUT
POR
February 1998
1/8
L6243DS
PIN CONNECTION
(Top view)
LOGIC SUPPLY SENSE
VDDA
1
24
23
22
21
20
19
18
17
16
15
14
13
POR DELAY
VDD SENSE OUT
POWER FAIL THRESHOLD
PARK VOLTAGE PROG
POR
2
OUTA
3
PARK
4
ENABLE
5
GND
6
GND
GND
7
GND
SENSE IN A
LOGIC SUPPLY FILTER
SENSE IN B
OUT B
8
ERROR OUT
ERROR IN
9
10
11
12
VREF
SENSE OUT
VDD B
PARK POWER
D96IN467
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
VS
VIN
VID
IO
Supply Voltage
14
0.3V to VS
±VS
V
Input Voltage
Differential Input Voltage
DC Output Current
1
A
A
Ip
Peak Output Current (non repetitive)
Total Power Dissipation (Tamb = 70°C)
Storage and Junction Temperature
1.2
Ptot
W
W
1.2
Tstg
-55 to +150
°C
PIN FUNCTIONS
Name
VDD
Function
Power supply.
GND
Common Ground.
Voltage Reference.
Vref
ENABLE
Input. Logic low will disable IC.
Input Power supply for the parking circuit.
PARK POWER
CURRENT SENSE OUT
ERROR AMP IN
ERROR AMP OUT
SENSE IN Α/Β
OUT A, B
Current sense operational amplifier output.
Error amplifier inverting input.
Error amplifier output.
Input for external sense resistors.
Outputs of the two Power Operational Amplifiers Connections for Voice coil Motor.
External input for parking. Low will activate the park procedure.
PARK
PARK VOLTAGE PROGRAM Input to set the park voltage.
POWER FAIL THRESHOLD
LOGIC SUPPLY SENSE
POR
Supply monitor threshold setting.
Sense the logic supply level
Power on reset output. Low will signal to the controller the failure of the logic supply.
Capacitor connection to set the power on reset delay.
Capacitor connection to filter the logic supply ripple
POR DELAY
LOGIC SUPPLY FILTER
2/8
L6243DS
THERMAL DATA
Symbol
Description
Value
Unit
Rth j-amb
Thermal Resistance Junction - Ambient
77 to 97
°C/W
ELECTRICAL CHARACTERISTICS
(VS = 12V, Tamb = 25°C; unless otherwise specified)
Symbol
Parameter
Supply Range
Test Condition
Min.
Typ.
Max.
Unit
V
VS
Id
4.5
13.2
Quiescent Drain Current
20
mA
°C
Tj
Thermal Shutdown Junction
Temperature
160
ERROR AMPLIFIER
Ib
Input Bias Current
1
µA
nA
mV
dB
IOS
VOS
Gv
Input Offset Current
Input Offset Voltage
300
+5
-5
Large Signal Open Loop Voltage
Gain
65
GBW
Gmin
IO+
Gain Bandwidth
3
MHz
Minimum Voltage Gain
Output Source Current
Output Sink Current
Slew-rate
5
9
6
6
2
mA
mA
IO–-
SR
V/µs
SENSE AMPLIFIER
RIN, Vref
Ad
Vref Input Impedance
KΩ
V/V
V/µs
MHz
KΩ
Differential Gain
8
1
3
SR
Slew-rate
GBW
Rin
Gain Bandwidth Product
Sense Input Impedance
Common Mode Rejection Ratio
1.5
55
CMRR
dB
POWER OP. AMP.
GV
Vd
Voltage Gain
26
dB
Total Output Voltage Drop
IO = 250mA
IO = 500mA
IO = 1A
450
750
1.15
mV
mV
V
1.5
Voff
Offset Voltage on Sense
Resistor
5
mV
BW
Bandwidth on Resistive Load
100
KHz
3/8
L6243DS
ELECTRICAL CHARACTERISTICS
(continued)
MONITORS AND CONTROL CIRCUIT
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
Vt2
Threshold Voltage at Logic
Supply Sense
4.2
4.5
V
VtL
Threshold Voltage at Power Fail
Threshold Input
1.375
1.4
1.435
V
HVt2
HVtL
Vll
Hysteresis on Vt2
Hysteresis on Vt2
Low Level Voltage
Enable Input Current
50
15
mV
mV
mV
µA
µA
µA
µA
V
Power on Reset = 2mA
Vi = 2.4V
250
500
100
Ie
Vi = 0.4V
–200
100
Ip
Input Current at Park
Vi = 2.4V
Vi = 0.4V
–200
0.8
Venl
Venh
Vph
Vpl
Enable Low Input Voltage
Enable High Input Voltage
Parking Input High Voltage
Parking Input Low Voltage
Power Fail Low Output Voltage
Parking Voltage Program Current
2
2
V
V
0.8
0.5
V
Vpfl
Iprog
Ich
Il = 2mA
V
100
5
µA
µA
Power On Reset Delay
Capacitor Charging
RF
Equivalent Input Resistance at
5V Filter Input
6.9
kΩ
FUNCTIONAL DESCRIPTION
BLOCK DESCRIPTION
The VCM Driver is controlled via two control sig-
nals, ENABLE, POWER ON RESET. An analog
input voltage, ERROR AMP IN, controls the polar-
ity and amplitude of the VCM driving current.
OUTPUT STAGE
It consists of two Power Op Amps connected in
bridge configuration.
Refer to figure two. This diagram is a repre-
sentation of the function of the VCM System.
Note that the signals with the bars represent the
"not true", or "non asserted" condition. From in-
itial power up, the system is held in the Park
Mode. Upon completion of the POWER UP RE-
SET DELAY the machine moves to Tristate Mode
or Run Mode, depending upon the condition of
the ENABLE input. If ENABLE is asserted, the
machine moves directly to Run Mode. If ENABLE
is not asserted, the machine moves to Tristate
Mode.
POWER ON RESET is an asynchronous output.
Additionally it affects the internal logic as a hard
wired reset and therefore if a supply failure occurs
during Tristate or Run state, the machine moves
directly back to the Park Mode.
While in Tristate Mode, the assertion of ENABLE
will move the machine to the Run Mode. Run
Mode will typically be the steady running state.
The deassertion of the ENABLE signal causes
the machine to move into Tristate. If it is desired
to perform an active Parking function, the PARK
input must be driven low by the external hard-
ware, or the the VCM can be driven to the Park
position via the ERROR AMP IN control voltage
CURRENT SENSE AMPLIFIER
Differential amplifier whose inputs are connected
to the sense lines and whose output is accessible
externally. Closing the loop will transform the
differential voltage signal from the sense lines into
a current signal for the Error Amplifier.
ERROR AMPLIFIER
Error amplifier which drives the output stage. The
input and the output pins are accessible exter-
nally.
POWER SUPPLY MONITOR OPERATION
The circuit monitors the logic supply voltage input
(typ 5V) and activates Power on Reset output
when such a supply drops below the safe operat-
ing limit. After the logic supply voltage reaches its
nominal value a delay capacitor has to be
charged [Tdelay = 3x2x10e5 x C sec] before
Power on Reset output change from low to high
level. Falling edges of Power on Reset are de-
µ
layed (typ 4 s) in order to disable the writing on
the disk before the Power on Reset is activated.
An additional supervisor circuit is present in the
4/8
L6243DS
FUNCTIONAL DESCRIPTION
Function
(continued)
Description
VDD input
This is the Power Supply input.
Input for the VCC supply monitor. The Threshold can be externally set via a voltage divider.
POWER FAIL
THRESH
V
CC SENSE OUT TTL compatible signal indicating the VCC supply has dropped below the POWER FAIL
Output
THRESHOLD.
LOGIC SUPPLY
SENSE input
This pin allows the monitoring of 5V supply. When a low voltage is detected POR is asserted
PARK POWER
input
This input is used during the Power Down/Power Fail Parking operation. When the supply goes
down, a typical Spindle Driver Circuit automatically tristates its output stages. During this time
the spindle motor spins freely and the stored energy is used to drive the VCM to the park
position. The generated BEMF is rectified and filtered across an external PARKING
CAPACITOR.
PROGRAMMABLE Used to set the voltage applied to the VCM during an Automatic Parking Operation.
PARK VOLTAGE
input
PARK
input
Logic signal asserted low, activates parking.
POWER ON RE-
SET output
Indicates an error condition to the external control and support circuitry. A Logic Supply Fail
condition automatically initiates a POWER ON RESET. Internal 30k Pullup to LSS.
POWER ON RE-
The intent of this input is to provide a time delay at power up. During this time, the POWER ON
SET DELAY in- RESET line will be asserted (low). A POWER ON RESET, will hold the system in the PARK
put
mode. Once the delay has timed out, the POWER ON RESET will be removed to allow the
external system to assume control. When applied in a Disk Drive Application, the POWER ON
RESET DELAY will be required to have a minimum duration which will ensure that the
Read/Write Heads can be fully parked.
ENABLE input
This signal originates at the external controller and, when asserted, allows the VCM Drivers to
operate. When deasserted the VCM Driver is forced into Tristate mode. During a POWER ON
RESET condition however, the parking operation is automatic and takes priority over the
ENABLE function. Only at the end of the POWER ON RESET DELAY will the ENABLE input
become active. If active parking is desired, it will be accomplished under control of the VIN
signal, otherwise it is an automatic function at power down.
VREF input
The reference voltage input is basically that voltage, at which the output current is zero.
Inverting input of error amplifier. The non inverting one is internally tied to Vref.
ERROR AMP IN
input
ERROR AMP OUT Error amplifier output pin. Open collector output.
output
OUTPUT A power Voice Coil power output.
output
OUTPUT B power Voice Coil power output.
output
SENSE AMP IN
A/B signal input
Sense amplifier input pins. The sense resistor is connected across these pins.
SENSE AMP OUT Output pin of sense amplifier.
signal output
LOGIC SUPPLY
FILTER
Capacitor connection to avoid false triggering
IC with a programmable threshold, which is set
by an external resistive divider. The TTL compat-
ible output can be used separately or connected
to Park input in order to park the head.
voltage is set by connecting an external resistor
between Park Voltage Program input and
µ
ground: (Vpark=Rext x Iref, Iref=100 A typ). Con-
necting ENABLE input to GND the driver will be
disabled (outputs in high impedance mode).
PARKING CIRCUIT OPERATIONT
THERMAL SHUTDOWN
The voice coil driver is switched into the parking
condition when Power on Reset output or Park in-
put are low. In such a condition a fixed voltage is
superimposed on the load and the value of such a
It will disable the IC when the junction tempera-
ture exceeds the threshold value above which the
device could be damaged.
5/8
L6243DS
Figure 1:
Application Circuit
VDD
13K
5V
1
22
17
24
2K
(*)
6,7,18,19
3
VIN
VCM
1.8nF
5K
1.5K
0.1µF
11
8
16
14
100
0.5
1.5K
10
9
21
D96IN468
(*) VALUES TO BE SET IN APPLICATION
(*)
(*)
Figure 2:
Application Circuit
LOGIC SUPPLY SENSE
POWER ON DELAY INPUT
POWER ON RESET
td
POWER ON RESET DELAY
D96IN470
6/8
L6243DS
SO24 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
2.35
0.10
TYP.
MAX.
2.65
0.30
2.55
0.51
0.32
15.60
7.60
MIN.
0.093
0.004
MAX.
0.104
0.012
0.100
0.0200
0.013
0.614
0.299
A
A1
A2
B
0.33
0.23
0.013
0.009
0.598
0.291
C
D
E
15.20
7.40
e
1.27
0,050
H
h
10.0
0.25
10.65
0.75
0.394
0.010
0.419
0.030
k
0° (min.), 8° (max.)
L
0.40
1.27
0.016
0.050
h x 45?
A1
K
B
e
A1
H
C
0.10mm
.004
L
Seating Plane
D
24
1
13
12
7/8
L6243DS
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-
THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express
written approval of SGS-THOMSON Microelectronics.
© 1998 SGS-THOMSON Microelectronics – Printed in Italy – All Rights Reserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
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