LXMG1811-05-6X MICROSEMI [Microsemi Corporation], LXMG1811-05-6X Datasheet - Page 5

• Manufacturer Part Number: LXMG1811-05-6X
• Description: 5V 6W CCFL Programmable Inverter Module
• Manufacturer: MICROSEMI [Microsemi Corporation]

Copyright © 2008
Rev 1.0, 2008-11-25
2.5V
0 to
Voltage Source,
Potentiometer
TM
0 < P.W. < 100% of period
DAC, or
500k
Figure 1A – PWM Brightness Control
10µs to 333µS
from System
PWM Signal
Figure 2 – Max Output Current
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: [phone]
Figure 1 – Brightness Control
BRITE
SLEEP
SET
(SET
H
H
L
L
1
P.W.
BRITE
LXMG1811-05-6x
SLEEP
SET
L=GND; H=Open
NC
1
SET
and SET
1
H
H
L
L
LXMG1811-05-6x
2
5V
V
SET
NC
IN
4.0mA
5.0mA
6.0mA
7.0mA
2
5V
V
BRITE
GND
2
IN
LXMG1811-05-6x
Inputs)
GND
RMS
RMS
RMS
RMS
V
V
LO
HI
V
V
T Y P I C A L A P P L I C A T I O N
LO
HI
TUBE
Analog Mixed Signal Group
CCFL
CCFL
TUBE
®
Microsemi
PanelMatch™ RangeMax™ LXMG1811-05-6x
5V 6W 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 an internal 234.2k pull-up to typically
4.2V to bias the pot. Logic levels may be used up to 5V,
however the inverter will reach maximum current at less
than 100% duty cycle.
approximately 2.3V divided by the logic high voltage
level; with 3.3V logic level this corresponds to about 70%
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
manufacture’s 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 an open
collector or open drain logic signal will allow you to
reduce the lamp current for situations where greater dim
range is required. 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 user’s responsibility since not all lamps are
designed to be overdriven.
output is open (lamp disconnected or broken) the inverter
will attempt to strike the lamp up to about 1.4 seconds,
after which (without success) the inverter will shutdown.
In this mode the inverter will draw about 5mA from V
In order to restart the inverter it is necessary to toggle the
sleep input or cycle the V
The inverter has a built-in fault timeout function. If the
LO
to the low voltage wire (wire with thinner insulation).
P
2
RODUCTION
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
IN
SLEEP
ATASHEET
input supply.
This can be calculated as
input.
LO
IN
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