LXMG1621-01 MICROSEMI, LXMG1621-01 Datasheet - Page 9

• Manufacturer Part Number: LXMG1621-01
• Description: CCFL Inverter Dual Lamp 4W 57KHz 20-Pin
• Manufacturer: MICROSEMI

Specifications of LXMG1621-01

• Number Of Lamps: 2
• Typical Input Voltage: 12 V
• Typical Lamp Operating Voltage: 625 Vrms
• Maximum Dimming: 100:1(Typ)
• Operating Temperature: 0 to 70 °C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 20
• Lead Free Status / Rohs Status: Compliant

Copyright © 2007
Rev. 1.2, 2010-08-20
delivering dimming ranges in the 250:1 range. As is widely
understood, these techniques will provide general capabilities
and actual system performance will vary with panel design,
CCFTs, ambient temperature and a number of other variables
outside the control of the inverter. These methods can be used
in conjunction with other techniques such as lamp heating and
matching.
Microsemi inverter in two ways:
indicated in Figure 9.
applying negative voltage to the brightness control input.
Applying more then –300mV to any inverter input will cause
inverter malfunction (see Absolute Maximum Ratings).
Figure 10 – Locating The Resistor on the LXMG1621-xx
The following application defines techniques capable of
Wide ratio (250:1) dimming can be accomplished using the
1. By varying the input voltage on the brightness pin as
TM
T1
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
Caution must be exercised when
R62
R63
U9
R60
R48
R61
R57
Q11
R31
Q10
W I D E R D I M M I N G A P P L I C A T I O N
R53
R54
Backside of Module
R51
U7
Analog Mixed Signal Group
R89
C37
®
Microsemi
RangeMAX™
Figure 9 – Average Lamp Current vs. V
Remove R61 for maximum dimming range or increase R61
value to desired minimum dim range setting (see figure 10).
Care should be exercised since at a low enough dim setting the
inverter will be unable to detect that the lamp has started and
will initiate lamp strike (kickoff) voltage. This will result in
lamp flicker. For repeatable low light levels the BRITE input
DC supply must be a very clean stable voltage source, at low
dim inputs.
you ensure that a minimum voltage above zero remain on the
BRITE input to prevent the above flicker problem.
minimum voltage may need to be adjusted for each individual
inverter module. If you are using a pot to control the BRITE
input then a separate trim pot on the low side would accomplish
the same goal.
operation than is necessary in a 100:1 dimming application.
quality at these dimming levels. At very low brightness levels,
even very small amounts of noise on the VBRITE line can cause
flicker on the display, so special care must be given to
grounding, filtering, and shielding the inverter from the digital
logic and clock signals.
D
IGITAL
2.
If you plan to completely remove R61 it is recommended that
Both methods discussed will provide a lower duty cycle
Careful consideration should be made with regard to display
By making a resistor value change on the module.
-100mV
.070
D
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0.7
IMMING
P
7
RODUCTION
D
UAL
0V
L
AMP
D
CCFL I
ATA
V
BRT_ADJ
S
NVERTER
HEET
LXMG1621-xx
BRITE
(V)
Voltage (per Lamp)
M
ODULE
2.5V
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