LXMG1618A-12-4X MICROSEMI [Microsemi Corporation], LXMG1618A-12-4X Datasheet - Page 5

• Manufacturer Part Number: LXMG1618A-12-4X
• Description: 12V 4W CCFL Programmable Inverter Module
• Manufacturer: MICROSEMI [Microsemi Corporation]

Copyright © 2007
Rev. 1.1, 2009-11-03
0V to
2.0V
TM
0 < P.W. < 100% of period
500k
DAC or
Pot
Figure 1A – PWM Brightness Control
10µs to 500µS
from System
PWM Signal
(output current set to maximum)
Figure 2 – Max Output Current
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, 800-877-6458, Fax: [phone]
Figure 1 – Brightness Control
BRITE
SLEEP
SET
(SET
H
H
L
L
P.W.
BRITE
1
LXMG1618A-12-4x
SET
L=GND; H= Open
NC
SLEEP
1
SET
1
and SET
LXMG1618A-12-4x
H
H
L
L
2
12V
SET
V
NC
IN
12V
5.0mA
5.5mA
6.0mA
6.5mA
2
V
GND
BRITE
LXMG1618A-12-4x
IN
2
Inputs)
GND
RMS
RMS
RMS
RMS
V
V
LO
HI
V
T Y P I C A L A P P L I C A T I O N
V
LO
HI
CCFL
TUBE
Analog Mixed Signal Group
CCFL
TUBE
®
Microsemi
PanelMatch™ "A Series"
12V 4W CCFL Programmable Inverter Module
The brightness control may be a voltage output DAC or
other voltage source, a digital pot or 500K manual pot. The
inverter contains effectively an internal 338k pull-up to 3V
to bias the pot, if desired; add a resistor to set the lower
threshold voltage above the absolute minimum dim level
capability. A PWM logic level signal (figure 1A) may be
used up to 5V; however the inverter will reach maximum
current at less than 100% duty cycle.
calculated as approximately 2V divided by the logic high
voltage level; with 3.3V logic level this corresponds to
about 60% duty cycle for maximum lamp current.
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 manufacturers. Generally the best
lamp lifetime correlates with driving the CCFL at the
manufacturer’s nominal current setting.
SET
adjust the 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 an 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 the peak output current, using
this technique the effective dim ratio can be increased.
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 user’s responsibility since
not all lamps are designed to be overdriven.
The inverter has a built-in fault timeout function. If the
output is open (lamp disconnected or broken) or shorted
the inverter will attempt to strike the lamp up to about one
second, after which (without success) the inverter will
shutdown. Supply current draw in the shutdown mode is
about 10mA. In order to restart the inverter it is necessary
to toggle the sleep input or cycle the V
LO
1
to the low voltage wire (wire with thinner insulation).
and SET
P
RODUCTION
HI
1
to high voltage wire from the lamp. Connect
and SET
2
inputs allow the user the flexibility to
LO
to circuit ground as this will defeat
2
D
(see Figure 2) inputs to select the
SLEEP
ATASHEET
LXMG1618A-12-4x
input.
IN
input supply.
However the
This can be
LO
Page 5
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