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LIN DOC #: 1611
RangeMAX
D IGITAL DIMMING CCFL INVERTER MODULE
T HE I NFINITE P OWER OF I NNOVATION
DESCRIPTION KEY FEATURES
RangeMAX Wide Range Dimming, Single
Output Inverter. The LXM1611 series of
Direct DriveTM CCFL (Cold Cathode Fluorescent Lamp) Inverter Modules are specifically
designed for driving LCD backlight lamps.
Similar to the LXM1610, the LXM1611 excels in applications where critical parameters
include very wide range dimmability, high
efficiency and reliable fail-safe design in a
small form factor.
Unlike the LXM1610 or any traditional
dimming CCFL inverters, the LXM1611 provides the designer a vastly superior display
brightness range. 100:1+ brightness range
is achievable with virtually any LCD display.
Our wide range dimming provides exceptional display readability at less than 1% of
full brightness, allowing both power savings
and low ambient light operating capability
(i.e. "night readable").
The LXM1611 is recommended for use in
panels with low-voltage insulation on the
lamp return wire.
RangeMAX Digital Dimming Technique. Digital dimming provides flicker-
free brightness control in any wide-range
dimming application. Dimming ratios greater
than 100:1 can be achieved. Incorporation
of a video synchronization feature allows
wide ratio dimming without the display disturbances and interference seen with competitive products.
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
The modules are equipped with a dimming
input that permits brightness control from an
external potentiometer or DC voltage source.
The resultant "burst drive" that energizes the
lamp was designed specifically to ensure that
no premature lamp degradation occurs. (See
"How RangeMAX Works" Section)
Wide Input Voltage Range. The modules convert unregulated DC voltage from the
system battery or AC adapter directly to highfrequency, high-voltage waves required to
ignite and operate CCFL lamps.
Direct Drive Technology. The module
design is based on a new Direct Drive topology, which provides a number of cost and
performance advantages. The LXM1611-01
series Direct Drive inverters eliminate the classic resonant inductor and capacitors, thus
reducing cost and allowing a 30% reduction
in module size.
Additional Features. Other benefits of
this new topology are fixed-frequency operation and secondary-side strike-voltage
regulation.
Strike-voltage regulation minimizes corona
discharge in the output transformer and related circuitry, providing longer life and higher
reliability. All LXM1611 modules feature both
open and shorted lamp protection.
The LXM1611 is fully customizable (electronically and mechanically) to specific customer requirements.
TM
LXM1611-01
P RELIMINARY DATA SHEET
■ RangeMAX Wide Range Dimming
■ 8V to 18V Input Voltage Range
■ 30% Smaller Than CS-ZVS Models
■ Easy To Use Brightness Control
■ MicroAmp SLEEP Mode
■ Output Short-Circuit Protection And
Automatic Strike-Voltage Regulation
■ 7.3mm Max. Module Height, 16mm Module
Width
■ Fixed Frequency Operation
APPLICATIONS
■ Notebook And Sub-Notebook Computers
■ Portable Instrumentation
■ Desktop Displays
■ Low Ambient Light Conditions (i.e. Aircraft
Cabins, Automobile)
BENEFITS
■ High Efficiency And Sleep Mode Feature
Extends Computer Battery Life
■ Smooth, Flicker Free 1-100% Full-Range
Brightness Control Gives Your Product A
High Quality Image
■ Output Open Circuit Voltage Regulation
Minimizes Corona Discharge For Long Life
And High Reliability
■ Power Efficient, "Low Brightness" Capability
Allows For Advanced Power Management
Power Used (Watts)
Copyright © 1999
Rev. 0.4 8/99
RANGEMAX VS. ANALOG DIMMING
5
4
3
2
1
0
30 45
Standard Analog
Dimming Inverter
60
75 90 105
Light Output (Nits
LinFinity's
RangeMAX
MODULE ORDER INFORMATION
L INF INITY MICROELECTRONICS INC.
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
PRODUCT HIGHLIGHT
■ RangeMAX technology allows the designer to operate
in a lower "brightness" and therefore at lower "power
consumption" than can be reached using traditional
analog dimming inverters.
■ Dotted line indicates area where panel variations and
parasitics will impact minimum light level with analog
dimming.
■ Data presented for a RangeMAX inverter driving a
13.3" LCD with a 1.2 Nit to 120 Nit brightness range.
The minimum power levels were 0.4 watts
(RangeMAX) vs. 2.1 watts (analog dimming) for a
power consumption savings of 1.7 watts.
LXM1611-01
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PRODUCT DATABOOK 1996/1997
LXM1611-01
RangeMAX
D IGITAL DIMMING CCFL INVERTER MODULE
P RELIMINARY DATA SHEET
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Supply Voltage (VIN)........................................................................................................................................................-0.3V to 18V
Output Voltage, no load .............................................................................................................................. Internally Limited to 1800V
Output Current............................................................................................................................................. 10.0mA
Output Power ........................................................................................................................................................................................ 6.0W
Input Signal Voltage (BRITE Input) ....................................................................................................................................... -0.3V to 6.5V
Input Signal Voltage (SLEEP, V
Ambient Operating Temperature ..............................................................................................................................................0°C to 70°C
SYNC(-)
, V
Inputs) ............................................................................................................... -0.3V to V
SYNC(+)
Storage Temperature Range ................................................................................................................................................... -40°C to 85°C
Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.
RECOMMENDED OPERATING CONDITIONS (R.C.)
This module has been designed to operate over a wide range of input and output conditions. However, best efficiency and performance
will be obtained if the module is operated under the condition listed in the 'R.C.' column. Min. and Max. columns indicate values beyond
which the inverter, although operational, will not function optimally.
Parameter
Symbol
Input Supply Voltage Range (Functional) V
Input Supply Voltage (Fully Regulated Lamp Current)
Output Power P
Brightness Control Input Voltage Range V
Lamp Operating Voltage V
Lamp Current (Full Brightness) I
Operating Ambient Temperature Range T
IN
O
BRT ADJ
LAMP
OLAMP
A
Recommended Operating Conditions
Min. R.C. Max.
81218V
91216V
45W
0.0 2.5 V
300 675 800 V
7.0 mA
070°C
(Internally Limited)
RMS
TM
RMS
IN
Units
RMS
RMS
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, these specifications apply over the recommended operating conditions and 25°C ambient temperature for the LXM1611.
Parameter
Symbol
Test Conditions Units
LXM1611-01
Min. Typ. Max.
Output Pin Characteristics
Full Bright Lamp Current I
Minimum Lamp Current (Note 2) I
Lamp Start Voltage V
Operating Frequency f
L (MAX)VBRT ADJ
L (MIN)VBRT ADJ
LS
O
= 2.5VDC, SLEEP = HIGH, Burst Duty = 100%, VIN = 9V
= 0VDC, SLEEP = HIGH, Burst Duty = 2%, VIN = 9V
0°C < TA < 40°C, V
V
= 2.5VDC, SLEEP = HIGH, VIN = 12V
BRT ADJ
≥ 7.0V
IN
DC
DC
6.3 7.0 7.7 mA
DC
DC
0.14 mA
1500 1800 V
52 57 62 KHz
BRITE Input
Input Current I
Input Voltage for Max. Lamp Current V
Input Voltage for Min. Lamp Current V
V
BRT
C
C
= 0V
BRT ADJ
I
O (LAMP)
I
O (LAMP)
DC
= 100% Duty Cycle
= Minimum Duty Cycle
-10 -12 -14 µA
2.5 2.6 V
00V
SLEEP Input
RUN Mode V
SLEEP Mode V
SLEEP (HI)
SLEEP (LO)
Input Current I
V
/ V
SYNC(-)
Logic High Level V
Logic Low Level V
Characteristics
SYNC(+)
SYNCH (HI)
SYNCH (LO)
Input Impedance Z
Pulse Width (Note 3) t
Input Frequency f
SLEEP
IN
PW
SYNC
SLEEP = 5.0V
2.2 V
IN
-0.3 0.8 V
120 180 µA
4.0 6.5 V
-0.3 1.0 V
60 66 75 kΩ
25 250 µs
49 150 Hz
Power Characteristics
Sleep Current I
IN (MIN)VIN
Note 2. Minimum lamp current required to maintain even light output may vary with display panel.
3. The module will be functional with pulse widths much larger than 250µs, but will have limited dimming.
= 15V
, SLEEP ≤ 0.8V
DC
10 50 µA
RMS
RMS
RMS
DC
DC
DC
V
DC
DC
DC
DC
DC
DC
2
Copyright © 1999
Rev. 0.4 8/99
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PRODUCT DATABOOK 1996/1997
P ATENT PENDING
TM
RangeMAX
Conn. Pin Description
CN1
CN1-1
CN1-2
CN1-3
CN1-4
CN1-5 SLEEP
CN1-6 BRITE
CN1-7
CN1-8 V
CN2
CN2-1 V
CN2-2 V
V
GND
V
SYNC(-)
SYNC(+)
IN
HI
LO
Input Power Supply. (8V ≤ VIN ≤ 18V)
Power Supply Return.
ON/OFF Control. (2.2V < SLEEP < V
Brightness Control (-0.3 to 2.5VDC). 2.5VDC gives maximum lamp current.
Vertical syncronization input, negative going.
Vertical syncronization input, positive going.
High voltage connection to high side of lamp. Connect to lamp terminal with shortest lead length.
DO NOT connect to ground.
Connection to low side of lamp. Connect to lamp terminal with longer lead length.
DO NOT connect to Ground.
D IGITAL DIMMING CCFL INVERTER MODULE
P RELIMINARY DATA SHEET
FUNCTIONAL PIN DESCRIPTION
= ON, -0.3V < SLEEP < 0.8V = OFF)
IN
25µs < tPW < 250µs, 49Hz < f
}
LXM1611-01
< 150Hz
SYNC
PHYSICAL DIMENSIONS
LXM1611-01
All dimensions are in inches (mm).
3.93 (100)
2.36 (60) 1.20 (30.5)
2.06 (52.25)
0.64
(16)
Warning!!
High Voltage
Present
Grounded Mounting Hole
CN1
0.287 Max. (7.3)
0.031 (0.79) max.
Ø 0.116 (2.95)
0.15
(3.85)
CN2
Connectors: Recommended Mate:
CN-1 = MOLEX 53261-0890 Pins: 50079-8100*, Housing: 51021-0800
* Loose (-8000, Chain) Recommended #26 AWG wiring
Copyright © 1999
Rev. 0.4 8/99
CN-2 = JST SM02(8.0) B-BHS-TB Pins: 5BH-001T-P0.5, Housing: BHR-03VS-1
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P ATENT PENDING
PRODUCT DATABOOK 1996/1997
LXM1611-01
D IGITAL DIMMING CCFL INVERTER MODULE
P RELIMINARY DATA SHEET
HOW RANGEMAX WORKS
LAMP VOLTAGE & LAMP CURRENT — Burst Mode Operation
(770V
(7.6mA
FIGURE 1 — 50% Burst Duty Cycle FIGURE 2 — 2% Burst Duty Cycle
TM
RangeMAX
(760V
(6.7mA
)
RMS
)
RMS
)
RMS
)
RMS
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.
Comparator
V
BRITE
0-2.5V
DC
Ramp
Ramp
Gen.
Transformer
Driver
FIGURE 3 — 2% Burst Duty Cycle (Expanded Time Base)
High Voltage
Transformer
V
HI
LAMP
V
SENSE
(760V
(6.7mA
)
RMS
)
RMS
V
V
SYNC(+)
SYNC(-)
I
SENSE
V
LO
FIGURE 4 — RangeMAX Block Diagram
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Copyright © 1999
Rev. 0.4 8/99
Page 5
PRODUCT DATABOOK 1996/1997
P ATENT PENDING
TM
RangeMAX
D IGITAL DIMMING CCFL INVERTER MODULE
P RELIMINARY DATA SHEET
HOW RANGEMAX WORKS (continued)
HIGHLIGHTS
■ On-board brightness control circuit includes a DC voltage
to pulse width converter that minimizes system design work
and system noise susceptibility. This provides a familiar
and convenient interface while reducing the potential for
externally induced noise which can cause lamp flicker.
■ An on-board oscillator operates the inverter BURST rate
above 95Hz, well beyond standard 50/60Hz video refresh
rates where the eye can perceive pulsing light.
■ RangeMAX inverter modules are designed to operate with
the burst frequency synchronized to the video frame rate.
This provides operation with no visible display disturbances
caused by beat frequencies between the lamps and video
frame rates.
TYPICAL APPLICATION
LXM1611-01
■ In applications with no access to a vertical sync, the in-
verter burst frequency can be allowed to "free run" at 95Hz.
non-synchronous mode, minor display disturbances
In this
can be found under certain video conditions. This performance may be acceptable for many applications, but synchronization must be used when no disturbance can be
tolerated.
■ Separate inputs are provided for negative and positive ver-
tical sync pulses so external inversion is not needed.
■ Separate feedback loops for lamp current and open circuit
voltage regulation insure reliable strike under all operating conditions, automatic over-voltage prevention with broken or failed lamps, and accurate lamp current regulation.
9-18V
V
DC
IN
£ 10k
2.5V
DC
BRITE
LXM1611-01
0V
5V
V
SYNC(-)
V
SYNC(+)
FIGURE 5 — Potentiometer Brightness Control
PWM Signal
from System
P.W.
£
100µs
0 £ P.W. £ 100% of period
Use 4.99k for 5V PWM amplitude, 15k for 3.3V PWM
*
amplitude, and omit for 2.5V PWM amplitude.
FIGURE 5A — PWM Brightness Control
SLEEP
V
SYNC(-)
4.99k
4.99k*
V
SYNC(+)
4.7µF
GND
V
HI
V
LO
BRITE
LXM1611-01
CCFL
TUBE
■ The brightness control may be a simple 10k
potentiometer or a voltage output DAC. A PWM signal
from a micro-controller may also be used with a suitable
filter such as shown in Figure 5A.
■ If synchronization to the video framerate is desired,
connect the vertical sync pulse from the system video
controller to the appropriate V
is negative going (
positive going (
), connect it to V
If no video synchronization is desired, leave both V
and V
■ If you need to turn the inverter ON/OFF remotely,
SYNC(+)
floating.
input. If the pulse
SYNC
), connect it to V
SYNC(+)
SYNC(-)
.
. If
SYNC(-)
connect a 3V or 5V logic signal to the SLEEP input. If
remote ON/OFF is not needed, connect the SLEEP input
to VIN or any other voltage greater than 2.2VDC.
■ Connect V
Connect V
insulation). Never connect V
this will defeat lamp current regulation. If both lamp
to high voltage wire from the lamp.
HI
to the low voltage wire (wire with thinner
LO
to circuit ground as
LO
wires have heavy high voltage insulation, connect the
longest wire to V
.
LO
RangeMAX INVERTERS
Also available in Dual
Output LXM1621-01 and
Quad Output LXM1641-01
versions for multiple lamp
applications.
Copyright © 1999
Rev. 0.4 8/99
RangeMAX and Direct Drive are trademarks of Linfinity Microelectronics Inc.
PRELIMINARY DATA - Information contained in this document is pre-production data, and is proprietary to LinFinity. It may
not modified in any way without the express written consent of LinFinity. Product referred to herein is offered in sample form
only, and Linfinity reserves the right to change or discontinue this proposed product at any time.
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