a6a595 Allegro MicroSystems, Inc., a6a595 Datasheet - Page 7

• Manufacturer Part Number: a6a595
• Description: Ic Pwr Drvr 8bit Address 20dip
• Manufacturer: Allegro MicroSystems, Inc.

INPUT
V
6A595
8-BIT SERIAL-INPUT,
DMOS POWER DRIVER
I
O
O
NORMAL LAMP IN-RUSH CURRENT
CURRENT LIMIT
(CHOPPING MODE)
ON ~ 40 s
OFF ~ 2.5 ms
t
av
V
V
(BR)DSX
O(ON)
I
AS
= 600 mA
I
TIME
O(chop)
NOT TO SCALE
DUT
Dwg. WP-008-1
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
OUT
+15 V
called in-rush currents) can contribute to poor lamp
reliability and destroy semiconductor lamp drivers.
Warming resistors protect both driver and lamp but use
significant power when the lamp is off while current-
limiting resistors waste power when the lamp is on.
Lamps with steady-state current ratings to 350 mA can be
driven by the A6A595 without the need for warming or
current limiting resistors.
lamp is initially turned on, the cold filament is at mini-
mum resistance and will normally allow a 10x peak in-
rush current. As the lamp warms up, the filament resis-
tance increases to its rated value and the lamp current is
reduced to its steady-state rating. When switching a lamp
with the A6A595, the internal chopping circuitry limits
the current (the solid line) to I
in the chopping mode until the lamp resistance increases
and the current requirement is less than I
effect of this current-limiting feature is that lamp turn-on
time will increase.
High incandescent lamp turn-on currents (commonly
As shown (the dashed line), when an incandescent
O(chop)
. The device will stay
O(chop)
. A side-