LXM1621-03 MICROSEMI, LXM1621-03 Datasheet - Page 9

• Manufacturer Part Number: LXM1621-03
• Manufacturer: MICROSEMI

Specifications of LXM1621-03

• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 22
• Lead Free Status / Rohs Status: Not Compliant

Copyright © 2000
Rev. 1.0a, 2005-02-07
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.
Linfinity 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).
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
Figure 10 – Locating The Resistor on the LXM1621-xx
I N T E G R A T E D
T1
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
R63
R62
Caution must be exercised when
U9
R60
R48
R61
P R O D U C T S
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
Linfinity Microelectronics Division
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.
D
-100mV
.070
IMMING
.14
0.7
P
7
RODUCTION
D
UAL
0V
L
AMP
D
CCFL I
ATA
V
BRT_ADJ
S
NVERTER
HEET
BRITE
(V)
LXM1621-xx
Voltage (per Lamp)
M
ODULE
2.5V
Page 9
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