SGS Thomson Microelectronics L9480VB, L9448VB, L9444VB Datasheet
ONE CHIP CAR ALTERNATOR REGULATOR
NO EXTERNALCOMPONENTS
PRECISETEMPERATURE COEFFICIENT
PRECISEREGULATEDVOLTAGE
HIGHOUTPUT CURRENT
SHORTCIRCUIT PROTECTED
REVERSEBATTERYPROTECTION
+ 80 V LOAD DUMP PROTECTION
LOW ENERGY SPIKEPROTECTION
THERMAL SHUTDOWN
VERYLOW START UP VOLTAGE
DESCRIPTION
The devices are a ”singlefunction” self-oscillating
voltage regulator for car alternators. Integrating
both the control section and the output power
L9444VB/L9448VB
L9480VB
ADVANCE DATA
TO220
ORDERING NUMBER: L9444VB
L9448VB
L9480VB
stage on a single chip, the devices require no external components, reducing significantlythe cost
of the systemand increasingreliability.
BLOCK DIAGRAM
October1992
This isadvanced informationon a new product now in development or undergoing evaluation. Details are subjectto change without notice.
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L9444VB -L9448VB - L9480VB
ABSOLUTE MAXIMUMRATINGS
Symbol Parameter Value Unit
V
S
I
clamp
I
out
T
j,Tstg
THERMAL DATA
Symbol Parameter Value Unit
R
th i-case
PIN CONNECTION (top view)
Transient Overvoltage :
Load Dump : 5ms ≤ T
Fall Time Constant ≤ 100ms, R
τ
f
Current into Low Energy Clamping Zener
=5µs;T
(T
rise
Maximum Output Current 5.5 A
Junction and Storage Temperature Range – 55 to + 150 °C
Thermal Resistance Junction-case Max. 3 °C/W
decay
≤ 10ms,
rise
≤ 2ms ; duty cycle ≤ 5%)
source
≥ 0.5Ω
80 V
100 mA
DEVICE OPERATION
The alternatorvoltage, rectifiedby the auxiliarydiode trio, is compared with an external reference
and the resulting signalswitches the outputstage,
drivingthe alternator fieldcoil.
As the regulator is a self-oscillating type, the
switching frequency depends on the whole system parameter set (including the alternator characteristics).
The regulator has an integrated filter in the voltage sensing path. Consequently it doesn’t need in the standard application- any external component.
Anywayan external capacitor (0.1 - 1µF) must be
inserted between V
and Ground guaranteeing
S
the correct behaviour of the device when the rectifying diodes feature very high switching spikes
that are not filteredby the devices.
This external capacitor must also be used when
the impedances of the cables connecting the al-
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ternator to the battery are so high to cause a superimposedripple on thealternatorvoltage higher
than3-4V.
The devices regulation voltage and the temperature coefficient may be independently set by
suited metal mask selections ; furthermore the
regulation voltage is trimmed within ± 1% of the
nominalvalue @25°C.
The devices have an unique -and patented- system to compensatethe self-heatingof the die due
to the power dissipated in the output stage. In this
way the internal referencevoltagetracks the case
temperaturerather than the die one.
Thedevice can withstand the reverse battery and
the load dump (up to 80V) ; They canabsorb,into
the internal clamping zeners, low energy spikes
up to a level of 100mA and its output is short circuit protected.
Finally the internal thermal shutdown avoids any
possible device damage due to overtemperature
problems.
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