LXM1611-01(1999) View Datasheet(PDF) - Microsemi Corporation
Part Name
Description
Manufacturer
LXM1611-01 Datasheet PDF : 5 Pages
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PATENT PENDING
LXM1611-01
PRODUCT DATABOOK 1996/1997
DIGITAL DIMMING CCFL INVERTER MODULE
PRELIMINARY DATA SHEET
HOW RANGEMAX WORKS
LAMP VOLTAGE & LAMP CURRENT — Burst Mode Operation
RangeMAXTM
(770VRMS)
(7.6mARMS)
(760VRMS)
(6.7mARMS)
FIGURE 1 — 50% Burst Duty Cycle
FIGURE 2 — 2% Burst Duty Cycle
Rather than using the traditional dimming technique of
varying lamp current magnitude to adjust light output,
RangeMAX inverters use a fixed lamp current value with
a duty cycle control method.
The lamp current burst width can be modulated from
100% (continuous lamp current) down to a 2% duty cycle,
allowing the lamp to be dimmed to less than 1% of its
full brightness.
As can be seen in Trace 4 of Figure 3 photo at right,
careful design consideration was given to controlling lamp
start voltage to softly start current flow. This eliminates
current overshoot that can result in premature cathode
wear and reduce lamp life.
(760VRMS)
(6.7mARMS)
FIGURE 3 — 2% Burst Duty Cycle (Expanded Time Base)
High Voltage
Comparator
Transformer
VHI
VBRITE
0-2.5V
DC
Ramp
Transformer
Driver
Ramp
Gen.
VSENSE
VSYNC(-)
VSYNC(+)
ISENSE
VLO
FIGURE 4 — RangeMAX Block Diagram
4
Copyright © 1999
Rev. 0.4 8/99
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