LXM1644-12-61 Microsemi Analog Mixed Signal Group, LXM1644-12-61 Datasheet - Page 5

• Manufacturer Part Number: LXM1644-12-61
• Description: MOD INVERTER CCFL QUAD 6W 12V
• Manufacturer: Microsemi Analog Mixed Signal Group
• Series: LXM1644-12-6xr
• Type: Inverters for CCFL and UV Lampsr

Specifications of LXM1644-12-61

• Voltage - Input: 12V
• Output: 2000V
• Size / Dimension: 7.40" L x 1.42" W x 0.31" H (188mm x 36mm x 8mm)
• Mounting Type: Chassis Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Copyright © 2002
Rev. 0.5b, 2004-11-03
Figure 2 – Max Output Current (Two Lamps)
I N T E G R A T E D
26% < P.W. < 100% of
Figure 1A – PWM Brightness Control
20K
Rx*
*Set Rx from 1.8K to 3.9K depending on panel
DAC or
Pot
10us to 125uS
PW M Signal
from System
(Output current set to maximum)
Figure 1 – Brightness Control
minimum lamp current requirements
period
BRITE
SLEEP
SET
(SET
H
H
L
L
P.W .
BRITE
LXM1644-12-61
SET
1
NC
L=GND; H=Open
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
SLEEP
1
LXM1644-12-61
SET
1
and SET
H
H
L
L
2
12V
SET
V
NC
IN1
12V
V
2
GND
10.0mA
12.0mA
14.0mA
16.0mA
IN 1
BRITE
2
P R O D U C T S
G ND
LXM1644-12-61
Inputs)
RMS
RMS
RMS
RMS
V
V
V
H1
H2
of two
LO
One
T Y P I C A L A P P L I C A T I O N
O ne of
two
Integrated Products
Microsemi
P
P
a
a
n
n
e
e
l
l
12V Quad 6W CCFL Programmable Inverter Module
M
M
a
a
t
t
The brightness control may be a voltage output DAC or
other voltage source, a digital pot or 20K manual pot. The
inverter contains an internal 10K pull-up to 3V to bias the
pot, add a 1.8K to 3.9K resistor to set the lower threshold
voltage. A 3.3V Logic Level PWM signal from a micro-
controller may also be used as shown in Figure 1A.
If you need to turn the inverter ON/OFF remotely, connect
to TTL logic signal to the
Connect V
V
Never connect V
lamp current regulation. If both lamp wires have heavy
high voltage insulation, connect the longest wire to V
This wire is typically white.
Use the SET
desired maximum output current. Using these two pins in
combination allows the inverter to match a wide variety of
panels from different manufactures. Generally the best
lamp lifetime correlates with driving the CCFL at the
manufactures nominal current setting. However the SET
and SET
current to the maximum allowable output current to
increase panel brightness at the expense of some reduced
lamp life.
Although the SET pins are designed such that just leaving
them open or grounding them is all that is needed to set the
output current, they can also be actively set. Using a open
collector or open drain logic signal will allow you to
reduce the lamp current for situations where greater dim
range is required, as an example in nighttime situations. In
conjunction with a light sensor or other timer the panel
could be set to higher brightness (maximum output
current) for daytime illumination and lower brightness
(minimum or typical output current) at nighttime. Since
the dim ratio is a factor of both the burst duty cycle and the
peak output current, using this technique the effective dim
ratio can be increased greater than the burst duty cycle
alone. Conversely the SET inputs could be used to
overdrive the lamp temporarily to facilitate faster lamp
warm up at initial lamp turn on. Of course any possible
degradation on lamp life from such practices is the users
responsibility since not all lamps are designed to be
overdriven.
The inverter has a built in fault timeout function. If the
output return is open (lamp disconnected or broken) or
shorted the inverter will attempt to strike the lamp for
several seconds. After about a second without success the
inverter will shutdown. In order to restart the inverter it is
necessary to toggle the sleep input or cycle the V
supply. In the timeout shutdown mode input drain current
will be about 8mA.
c
c
LO
h
h
™
™
to the low voltage wire (wire with thinner insulation).
P
2
RELIMINARY
inputs allow the user the flexibility to adjust the
HI
1
to high voltage wire from the lamp. Connect
and SET
LO
to circuit ground as this will defeat
2
D
(see Figure 2) inputs to select the
SLEEP
ATASHEET
input.
LXM1644-12-61
IN1
input
LO
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