T
H E
The LX1686 Backlight Controller IC
provides all the control functions needed
to implement Linfinity’s direct drive in-
verters used to operate cold cathode fluo-
rescent lamps (CCFL’s). This IC can be
used to control single or multiple-lamp
configurations. CCFL’s are used for back
or edge lighting of liquid crystal flat panel
displays (LCD’s) and typically find appli-
cation in notebook computers, web
browsers, automotive and industrial in-
strumentation, and entertainment sys-
tems.
trolled lamp current burst circuit that
can provide a >100:1 dimming range from
a simple zero to 2.5V potentiometer in-
put.
easily synchronized to the LCD panel’s
frame rate to prevent interference from
optical beat frequencies.
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
The LX1686 includes a PWM con-
I
N F I N I T E
0
The PWM dimming burst rate is
5
4
3
2
1
30
11861 W
P
45
O W E R
Standard Analog
Dimming Inverter
Light Output (Nits)
ESTERN
60
D E S C R I P T I O N
O F
L
A
I N
75
Note: All surface-mount packages are available in Tape & Reel.
VENUE
I
Append the letter "T" to part number. (i.e. LX1686CPWT)
LinFinity's
RangeMAX
F
N N O V A T I O N
I N I T Y
, G
90
clude a new dual feedback contol loop
that permits regulation of maximum lamp
strike voltage as well as lamp current.
Regulating maximum lamp voltage per-
mits the designer to provide for ample
worst case lamp strike voltage while at
the same time conservatively limit maxi-
mum open circuit voltage.
generation technique enables the mod-
ule designer to optimize high voltage
transformer design for maximum oper-
ating efficiency with no power dissipat-
ing overhead to guarantee strike capa-
bility.
nant, oscillator-controlled PWM regu-
lation method. The LX1686 allows a
wide choice of fixed operating frequen-
cies to match lamp current frequency to
the lamp’s most efficient operating point,
and to minimize high frequency interfer-
ence.
P A C K A G E O R D E R I N F O
ARDEN
Safety and reliability features in-
An innovative new strike voltage
Direct drive topology is a non-reso-
P R O D U C T H I G H L I G H T
0 to 85
105
T
A
(°C)
M
G
ROVE
I C R O E L E C T R O N I C S
, CA. 92841, 714-898-8121, F
PW
RangeMAX
Light emitted by a CCFL is proportional to the current
flowing through it. 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 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.
LX1686CPW
Plastic TSSOP
24-pin
D
I G I T A L
P
R E L I M I N A R Y
D
I M M I N G
TM
I
N C
AX
: 714-893-2570
.
RangeMAX
Synchronizable To Display Video Frequency
High Voltage Feedback Loop Directly
Controls Maximum Open Lamp And
Minimum Strike Voltages
Transformer Protected From Over-Heating
During Lamp Striking
Micro-Amp Sleep Mode
User-Programmable Fixed Frequency
Operation
Under-Voltage Lockout Feature With Power-
Up Reset
Built-In Soft-Start Feature
Operates With 3.3V or 5V Power Supplies
100mA Output Drive Capability
Notebooks
Instrumentation Displays
Desktop Computer Monitors
Low Ambient Light Displays (used in
Aircraft, Automobiles, and Hand-held
Equipment)
Extemely High Efficiency From 3.3V or 5V
Power Supplies
Lower Cost Than Conventional Buck / Royer
Inverter Topologies
Improved Lamp Strike Capability
Improved Over-Voltage Control
C C F L C
K E Y F E A T U R E S
A P P L I C A T I O N S
D
A T A
B E N E F I T S
TM
Wide Range Dimming (>100:1)
O N T R O L L E R
S
LX1686
H E E T
I C
1