LX1686E Datasheet, PDF (1/8 Pages) Microsemi Corporation – Digital Dimming CCFL Controller IC

LX1686E
TM
®
Digital Dimming CCFL Controller IC
PRODUCTION DATA SHEET
DESCRIPTION
The LX1686E Backlight Controller Safety and reliability features include
IC provides all the control functions a new dual feedback control loop that
needed to implement Microsemi’s permits regulation of maximum lamp
direct drive inverters used to operate strike voltage as well as lamp current.
cold cathode fluorescent lamps Regulating maximum lamp voltage
(CCFL’s). This IC can be used to permits the designer to provide for
control single or multiple-lamp ample worst case lamp strike voltage
configurations. CCFL’s are used for while at the same time conservatively
back or edge lighting of liquid crystal limit maximum open circuit voltage.
flat panel displays (LCD’s) and An innovative new strike voltage
typically find application in notebook generation technique enables the
computers, web browsers, automotive module designer to optimize high
and industrial instrumentation, and voltage transformer design for
entertainment systems.
maximum operating efficiency with no
The LX1686E includes a PWM power dissipating overhead to guarantee
controlled lamp current burst circuit strike capability
that can provide a > 100:1 dimming Direct drive topology is a non-
range from a simple zero to 2.5V resonant, oscillator-controlled PWM
potentiometer input. The PWM regulation method. The LX1686E
dimming burst rate is easily allows a wide choice of fixed operating
synchronized to the LCD panel’s frame frequencies to match lamp current
rate to prevent interference from frequency to the lamp’s most efficient
optical beat frequencies.
operating point, and to minimize high
frequency interference.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
Protected by U.S. Patents 5,615,093; 5,923,129; 5,930,121; 6,198,234; Patents Pending
PRODUCT HIGHLIGHT
5
Standard Analog
4
Dimming Inverter
KEY FEATURES
ƒ RangeMAX™ Wide Range
Dimming (>100:1)
ƒ Synchronizable to Display Video
Frequency
ƒ High Voltage Feedback Loop
Directly Controls Maximum Open
Lamp
ƒ Micro-Amp Sleep Mode
ƒ User Programmable Fixed
Frequency Operation
ƒ Under-Voltage Lockout Feature
With Power-Up Reset
ƒ Built-In Soft-Start Feature
ƒ Operates With 3.3V or 5V power
Supplies
ƒ 100mA Output Drive Capability
APPLICATIONS
ƒ Notebooks
ƒ Instrumentation Display
ƒ Desktop Computer Monitors
ƒ Low Ambient Light Displays
(used in Aircraft, Automobiles,
and Hand-Held Equipment)
BENEFITS
ƒ Extremely High Efficiency From
3.3V to 5V Power Supplies
ƒ Lower Cost Than Conventional
Buck / Royer Inverter Topologies
ƒ Improved Lamp Strike Capability
ƒ Improved Over-Voltage Control
3
Microsemi's
RangeMAX
Light emitted by a CCFL is proportional to the current flowing through it.
2
There are two ways to control the current: by adjusting the amplitude of a
continuous AC current; or, as with RangeMAX technology, by varying the
amount of time a burst of full current is present. RangeMAX technology
1
frees the backlight inverter module designer to operate in a lower
brightness and lower power consumption mode than is possible with
conventional amplitude control methods.
0
0
30
45
60
75
90
105
Light Output (Nits)
Copyright © 2004
Rev. 1.1, 2006-02-27
T_A (°C)
0 to 85
-40 to 85
PACKAGE ORDER INFO
Plastic TSSOP
PW _24-PIN
RoHS compliant / Pb-free
LX1686ECPW
LX1686EIPW
Note: Available in Tape & Reel. Append the
letters “TR” to the part number. (i.e.
LX1686ECPW-TR)
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
Page 1