LXM1641-02 [MICROSEMI]
DIGITAL DIMMING DUAL LAMP CCFL INVERTER MODULE; 数字调光双灯管CCFL逆变器模块
| 型号： | LXM1641-02 |
| 厂家： | 
Microsemi |
| 描述： | DIGITAL DIMMING DUAL LAMP CCFL INVERTER MODULE |
| 文件： | 总11页 (文件大小：232K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
T H E I N F I N I T E P O W E R O F I N N O V A T I O N
P R E L I M I N A R Y D A T A S H E E T
DESCRIPTION
KEY FEATURES
■ RangeMAX Wide Range Dimming
■ 8V to 16V Input Voltage Range
■ Small Form Factor
■ Easy To Use Brightness Control
■ MicroAmp SLEEP Mode
■ Output Short-Circuit Protection And
Automatic Strike-Voltage Regulation
■ Fixed Frequency Operation
RangeMAX Wide Range Dimming, Quad
Output Inverter. The LXM1641 Direct
DriveTM CCFL (Cold Cathode Fluorescent
Lamp) Inverter Modules are specifically de-
signed for driving LCD backlight lamps.
Similar to the LXM1640, the LXM1641 ex-
cels in applications where critical parameters
include very wide range dimmability, high ef-
ficiency and reliable fail-safe design in a small
form factor. These 12 volt input modules are
specifically designed with desktop and indus-
trial applications in mind.
Unlike the LXM1640 or any traditional
dimming CCFL inverters, the LXM1641 pro-
vides the designer a vastly superior display
brightness range. 1000:1+ brightness range
is achievable with a standard LCD display (see
Application Section). Our wide range dim-
ming provides exceptional display readability
at less than 1% of full brightness, allowing
both power savings and low ambient light op-
erating capability (i.e. "night readable").
RangeMAX Digital Dimming Tech-
nique. Digital dimming provides flicker-free
brightnesscontrolinanywide-rangedimming
application. Dimming ratios greater than
1000:1 can be achieved. Incorporation of a
video synchronization feature allows wide
ratio dimming without the display distur-
bances and interference seen with competi-
tive products.
lamp was designed specifically to ensure that
no premature lamp degradation occurs (see
"How RangeMAX Works" Section).
Failsafe Feature For Multiple Lamp Ap-
plications. Our multi-output inverters are
designed to keep your application operating
at near normal brightness in the event that a
lamp fails. This allows the display to remain
"on-line" until lamp replacement is conve-
nient.
Direct Drive Technology. The module
design is based on a new patented1 Direct
Drive topology, which provides a number of
cost and performance advantages. The
LXM1641-xx Direct Drive inverters eliminate
the classic resonant inductor and capacitors,
thus reducing cost and allowing a substantial
reduction in module size.
Universal Connector Configuration.
Linfinity's multiple lamp inverters include a
built in connector array for the most com-
mon LCD lamp configurations.
Additional Features. Other benefits of
this new topology are fixed-frequency opera-
tion and secondary-side strike-voltage regu-
lation.
■ Universal Connector Configuration
APPLICATIONS
■ Hi-Brite Displays
■ Desktop Displays
■ Low Ambient Light Conditions (i.e. Aircraft
Cabins, Automobile)
■ Industrial Applications
BENEFITS
■ High Efficiency Reduces Heating Problems
■ Smooth, Flicker Free 0-100% 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
Strike-voltage regulation minimizes corona
discharge in the output transformer and re-
lated circuitry, providing longer life and higher
reliability. All LXM1641 modules feature
both open and shorted lamp protection.
The LXM1641 is fully customizable (elec-
tronically and mechanically) to specific cus-
tomer requirements.
■ Power Efficient, "Low Brightness" Capability
Allows For Advanced Power Management
Themodulesareequippedwithadimming
input that permits brightness control from an
external potentiometer or DC voltage source.
The resultant "burst drive" that energizes the
1 US Patent Numbers: 5923129 & 5930121
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
MODULE ORDER INFORMATION
Inverter Mates Directly
to Panel Connectors
Part Number
Application
JST BHR-03VS-1 (3-pin) &
JST BHR-04VS-1 (4-pin)
LXM1641-01
Quad Lamp Panels
LXM1641-02
LXM1641-03
Sharp 18.1" Panel
JST XHP-9 (9-pin)
LG Electronics 18.1" Panel
JST BHSR-02VS-1 (2-pin)
L I N F I N I T Y M I C R O E L E C T R O N I C S I N C .
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
Copyright © 1999
Rev. 0.7 12/99
1
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Supply Voltage (VIN)....................................................................................................................................................... -0.3V to 16V
Output Voltage, no load ..............................................................................................................................Internally Limited to 1800VRMS
Output Current ............................................................................................................................................ 10.0mARMS (Internally Limited)
Output Power (per Lamp) .................................................................................................................................................................... 6.0W
Input Signal Voltage (BRITE Input) ....................................................................................................................................... -0.3V to 6.5V
InputSignalVoltage(SLEEP,VSYNC Inputs) ...................................................................................................................................-0.3V to VIN
AmbientOperatingTemperature ....................................................................................................................................................0°C to 70°C
StorageTemperatureRange .........................................................................................................................................................-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.
Recommended Operating Conditions
Parameter
Symbol
Units
Min.
R.C.
Max.
Input Supply Voltage Range (Functional)
LXM1641-01, -02
LXM1641-03
8
10
9
12
12
12
12
4
16
14
V
V
Input Supply Voltage
LXM1641-01, -02
LXM1641-03
16
V
(Fully Regulated Lamp Current)
Output Power (per Lamp)
10.8
13.2
5
V
PO
VBRT ADJ
VLAMP
IOLAMP
TA
W
Brightness Control Input Voltage Range
Lamp Operating Voltage
0.0
2.5
800
V
300
675
7.0
VRMS
mARMS
°C
Lamp Current (Full Brightness - per Lamp)
Operating Ambient Temperature Range
0
70
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, these specifications apply over the recommended operating conditions and 25°C ambient temperature for the LXM1641.
LXM1641-xx
Parameter
Symbol
Test Conditions
Units
Min. Typ.
Max.
Output Pin Characteristics
Full Bright Lamp Current
(per Lamp)
1641-01,-02
1641-03
IL (MAX)
IL (MIN)
VBRT ADJ = 2.5VDC, SLEEP = HIGH, Burst Duty = 100%, VIN = 9VDC
VBRT ADJ = 2.5VDC, SLEEP = HIGH, Burst Duty = 100%, VIN = 12VDC 7.2
VBRT ADJ = 0VDC, SLEEP = HIGH, Burst Duty = 2%, VIN = 9VDC
6.3
7.0
8.0
7.7
8.8
mARMS
mARMS
mARMS
mARMS
VRMS
Minimum Lamp Current (per Lamp)
(Notes 2 & 3)
0.14
0.035
VBRT ADJ = -50mVDC, SLEEP = HIGH, Burst Duty = 0.5%, VIN = 9VDC
1500
52
1800
62
Lamp Start Voltage
VLS
fO
0°C < TA < 40°C, VIN ≥ 10.8VDC
57
KHz
Operating Frequency
VBRT ADJ = 2.5VDC, SLEEP = HIGH, VIN = 12VDC
BRITE Input
Input Current
IBRT
VC
VBRT ADJ = 0VDC
-6
-8
2.5
0
-10
2.6
0
µADC
VDC
Input Voltage for Max. Lamp Current
Input Voltage for Min. Lamp Current
(Note 3)
IO (LAMP) = 100% Duty Cycle
IO (LAMP) = 2% Duty Cycle
IO (LAMP) = 0.5% Duty Cycle
VC
VDC
mVDC
-50
SLEEP Input
RUN Mode
SLEEP Mode
Input Current
VSLEEP (HI)
VSLEEP (LO)
ISLEEP
2.2
-0.3
70
VIN
0.8
100
VDC
VDC
µADC
75
SLEEP = 5.0V
Note 2. Minimum lamp current required to maintain even light output may vary with display panel.
3. See 1000:1 Dimming Application section for details.
Copyright © 1999
Rev. 0.7 12/99
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P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
ELECTRICAL CHARACTERISTICS (Continued)
LXM1641-xx
Min. Typ.
Parameter
Symbol
Test Conditions
Units
Max.
VSYNC Characteristics
Logic High Level
Logic Low Level
Input Impedance
Pulse Width (Note 4)
Input Frequency
VSYNC (HI)
VSYNC (LO)
ZIN
4.0
-0.3
60
6.5
1.0
75
250
150
VDC
VDC
kΩ
µs
66
5
25
tPW
49
Hz
fSYNC
Power Characteristics
Sleep Current
IIN (MIN)
VIN = 12VDC , SLEEP ≤ 0.8V
50
µADC
Note 4. The module will be functional with pulse widths much larger than 250µs, but will have limited dimming.
Copyright © 1999
Rev. 0.7 12/99
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P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
PHYSICAL DIMENSIONS
LXM1641-01
All dimensions are in inches (mm)
6.39 (161)
5.04 (128)
0.65 (16.5)
CN1
0.96
(24.5)
0.30 (7.5)
Top Side
1.03
(26.2)
1.05
(26.6)
1.05
(26.6)
Ø 0.138 (3.5)
Grounded Mounting Hole - 2 plcs
4.25 (107.925)
Bottom Side
1.26
(32)
0.338 (8.6) Max.
Warning!!
High Voltage Present
At All Output
Connectors
0.060 (1.52) max.
0.13
(3.3)
FIGURE 1 — LXM1641-01 Physical Dimensions
Functional Pin Description
Conn.
Pin
Description
CN1
CN1-1, 2
CN1-3, 4
CN1-5
VIN
Input Power Supply. (8V ≤ VIN ≤ 16V)
GND
SLEEP
BRITE
VSYNC
Power Supply Return.
ON/OFF Control. (2.2V < SLEEP < VIN = ON, -0.3V < SLEEP < 0.8V = OFF)
Brightness Control (-0.3V to 2.5VDC). 2.5VDC gives maximum lamp current.
Vertical syncronization input. 49Hz < fSYNC < 150Hz
CN1-6
CN1-7, 8
CN2 thru CN7: Refer to Figure 2
Copyright © 1999
Rev. 0.7 12/99
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P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
CONNECTOR SCHEMATIC
CN1
VHI2
VHI4
Inverter
Inverter
Output 2
8
1
Output 4
VHI1
VHI3
Inverter
Inverter
Output 1
Output 3
1
2
2
4
1
2
3
1
3
2
1
N.C.
CN4
CN6
N.C.
3
4
1
3
CN2
CN3
2
2
1
CN5
CN7
FIGURE 2 — LXM1641-01 Connector Schematic
Note: CN2 and CN3 (shown with dashed lines) are located on the opposite side of the PCB from CN1, CN4,
CN5, CN6, and CN7. Their pin numbers are shown as viewed looking through the printed circuit board.
Connectors:
Mates With:
CN1 = MOLEX 53261-0890
Pins: 50079-8100*, Housing: 51021-0800
* Loose (-8000, Chain) Recommended #26 AWG wiring
CN2, CN3 = JST SM04(4.0)B-BHS-1-TB
CN4, CN7 = JST SM03(4.0)B-BHS-1-TB
CN5, CN6 = JST SM02(8.0)B-BHS-1-TB
JST BHR-04VS-1
JST BHR-03VS-1
JST BHR-03VS-1
Connection Rules
1. Always install FOUR (4) lamps. Operating with fewer lamps may overdrive lamp current at maximum brightness settings.
2. Verify lamp wiring before connecting lamps to the inverter module. Connecting multiple lamps to one of the four inverter output
circuits will result in reduced brightness. The LXM1641-01 module connectors are wired per industry standard. The lamphot wires
(high voltage wires) are always on pin 1 or 2, and the cold wire (low voltage wire) is always on pin 3 or 4.
Copyright © 1999
Rev. 0.7 12/99
5
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
PHYSICAL DIMENSIONS
LXM1641-02
For Direct Connection to Sharp: LQ181E1DG01 (18.1" TFT, 4 lamp)
9.84 (250)
7.95 (202)
0.94
(24)
3.70 (94)
2.44 (62)
9.06 (230)
0.30
(7.5)
CN1
1.26
(32)
1.06
(27)
0.96
(24.5)
Ø 0.138 (3.5) Dia. Hole
4 Places (plated)
0.20 (5)
FIGURE 3 — LXM1641-02 Physical Dimensions
All dimensions are in inches (mm)
Connectors:
Mates With:
CN1 = MOLEX 53261-0890
CN2, CN3 = JST S9B-XH-A
Pins: 50079-8100, Housing: 51021-0800
XHP-9
Functional Pin Description
Connector
Pin #
Pin Name
Description
CN1-1, 2
CN1-3, 4
CN1-5
CN1-6
CN1-7, 8
CN2-1
CN2-2, 3
CN2-4
CN2-5, 6
CN2-7
VIN
GND
SLEEP
BRITE
VSYNC
VHI1
Input Power Supply (8V to 16V)
Power Supply Return
ON / OFF Control (2.2V < SLEEP < VIN = ON, -0.3V < SLEEP < 0.8V = OFF
Brightness Control (-0.3V to 2.5V), 2.5V gives max. lamp current
Vertical Sync Input, negative going. 49Hz < fSYNC < 150Hz
High-voltage connection to high side of lamp 1
No Connect
N.C.
VHI2
N.C.
VLO
High-voltage connection to high side of lamp 2
No Connect
Connection to low side of lamp 2
No Connect
CN2-8
N.C.
CN2-9
CN3-1
CN3-2, 3
CN3-4
CN3-5, 6
CN3-7
VLO
VHI3
N.C.
Connection to low side of lamp 1
High-voltage connection to high side of lamp 4
No Connect
VHI4
N.C.
VLO
High-voltage connection to high side of lamp 3
No Connect
Connection to low side of lamp 3
No Connect
CN3-8
N.C.
CN3-9
VLO
Connection to low side of lamp 4
Copyright © 1999
Rev. 0.7 12/99
6
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
PHYSICAL DIMENSIONS
LXM1641-03
For Direct Connection to LG LM181E1 18.1" SXGA
9.84 (250)
7.95 (202)
0.94
(24)
3.70 (94)
2.44 (62)
CN8
0.30
CN10
CN11
CN1
1.26
(32)
(7.5)
1.06
(27)
CN9
0.96
Ø 0.138 (3.5) Dia. Hole
0.20 (5)
(24.5)
4 Places (plated)
Note: Connectors CN8, CN9, CN10, and CN11 are mounted
on bottom side of board. Shown looking through board.
FIGURE 4 — LXM1641-03 Physical Dimensions
All dimensions are in inches (mm)
Connectors:
Mates With:
CN1 = MOLEX 53261-0890
CN8, CN9, CN10, CN11 = JST SM02B-BHSS-1-TB
Pins: 50079-8100, Housing: 51021-0800
BHSR-02VS-1
Functional Pin Description
Connector
Pin #
Pin
Description
CN1-1, 2
CN1-3, 4
CN1-5
CN1-6
CN1-7, 8
CN8-1
VIN
GND
SLEEP
BRITE
VSYNC
VHI1
Input Power Supply (10V to 14V)
Power Supply Return
ON / OFF Control (2.2V < SLEEP < VIN = ON, -0.3V < SLEEP < 0.8V = OFF)
Brightness Control (-0.3V to 2.5V), 2.5V gives max. lamp current
Vertical Sync Input, negative going. 49Hz < fSYNC < 150Hz
High-voltage connection to high side of lamp 1
Connection to low side of lamp 1
CN8-2
VLO
CN9-1
CN9-2
VHI1
VLO
High-voltage connection to high side of lamp 2
Connection to low side of lamp 2
CN10-1
CN10-2
CN11-1
CN11-2
VHI1
VLO
VHI1
VLO
High-voltage connection to high side of lamp 3
Connection to low side of lamp 3
High-voltage connection to high side of lamp 4
Connection to low side of lamp 4
Copyright © 1999
Rev. 0.7 12/99
7
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
TYPICAL CONNECTION CONFIGURATIONS
These examples illustrate three typical
LCD wiring configurations that are
accomodated by Linfinity's unique
connector array. Linfinity inverters
have multiple lamp connector styles
that are common to the industry,
which are duplicated at both ends of
the module. This permits many
variations of module mounting and
interconnectivity configurations.
1
1
CN6 CN7
CCFL Lamps
CN4 CN5
1
1
Desktop Display
1
CCFL Lamps
CN3
CCFL Lamps
CN2
1
Desktop Display
* Connectors CN2 and CN3 are on the bottom side of the inverter.
View shown is looking through the board.
1
1
CCFL Lamps
CN6 CN7
CCFL Lamps
CN4 CN5
1
1
Desktop Display
FIGURE 5 — Connectivity Configuration Examples
Copyright © 1999
Rev. 0.7 12/99
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P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
HOW RANGEMAX WORKS
LAMP VOLTAGE & LAMP CURRENT — Burst Mode Operation
(760VRMS
)
(770VRMS
)
(6.7mARMS
)
(7.6mARMS
)
FIGURE 6 — 50% Burst Duty Cycle
FIGURE 7 — 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.
(760VRMS
)
As can be seen in Trace 4 of Figure 8, careful design
consideration was given to controlling lamp start voltage
to softly start current flow. This eliminates current over-
shoot that can result in premature cathode wear and re-
duce lamp life.
(6.7mARMS
)
FIGURE 8 — 2% Burst Duty Cycle (Expanded Time Base)
High Voltage
Transformer
Comparator
VBRITE
VHI1
Ramp
Transformer
Driver
0-2.5V
DC
Ramp
Gen.
VSENSE
VSYNC
ISENSE
VLO
FIGURE 9 — RangeMAX Block Diagram
Copyright © 1999
Rev. 0.7 12/99
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P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
HOW RANGEMAX WORKS (continued)
HIGHLIGHTS
■ In applications with no access to a vertical sync, the in-
verter burst frequency can be allowed to "free run" at 95Hz.
In thisnon-synchronous mode, minor display disturbances
may be found under certain video conditions. This per-
formance is acceptable for many applications, but synchro-
nization must be used when no disturbance can be toler-
ated.
■ Separate feedback loops for lamp current and open circuit volt-
age regulation insure reliable strike under all operating conditions,
automatic over-voltage prevention with broken or failed lamps,
and accurate lamp current regulation.
■ 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 100:1 DIMMING APPLICATION
9VDC- 16VDC
VIN
■ 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 11.
■ If synchronization to the video framerate is
desired, connect the vertical sync pulse from the
system video controller to the appropriate VSYNC input.
If no video synchronization is desired, connect VSYNC
to ground.
2.5VDC
VHI4
VHI3
VHI2
VHI1
£10k
BRITE
LXM1641-xx
■ If you need to turn the inverter ON/OFF remotely,
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.
5V
SLEEP
VSYNC
0V
GND VLO
■ Connect VHI to high voltage wire from the lamp.
Connect VLO to the low voltage wire (wire with
thinner insulation). If both lamp wires have
heavy high voltage insulation, connect the
longest wire to VLO. VLO is connected directly to
ground (GND pin) on the inverter PCB. Always
insure a good lamp return by using a wire. Do
not rely on a chassis ground connection.
VSYNC
FIGURE 10 — Potentiometer Brightness Control
PWM Signal
from System
4.99k
BRITE
4.7µF
P.W.
4.99k*
LXM1641-xx
£
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 11 — PWM Brightness Control
Copyright © 1999
Rev. 0.7 12/99
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RangeMAXTM
LXM1641-01/-02/-03
DIGITAL DIMMING QUAD LAMP CCFL INVERTER MODULE
P R E L I M I N A R Y D A T A S H E E T
1000:1 DIMMING APPLICATION
The following application defines techniques capable of deliver-
ing dimming ranges in the 250:1 and 1000:1 range. As is widely
understood,thesetechniqueswillprovidegeneralcapabilitiesandactual
systemperformancewillvarywithpaneldesign,CCFTs,ambienttem-
peratureandanumberofothervariablesoutsidethecontrolofthe
inverter. Thesemethodscanbeusedinconjunctionwithothertech-
niquessuchaslampheatingandmatching.
7
0.7
Wideratio(1000:1)dimmingcanbeaccomplishedusingtheLinfinity
inverterintwoways:
.14
.070
1) By varying the input voltage on the brightness pin as
indicated in Figure 12. Caution must be exercised when
applying negative voltage to the brightness control input.
Applying more than -300mV to any inverter input will cause
inverter malfunction (see Absolute Maximum Ratings).
-100mV
0V
2.5V
VBRT ADJ (V)
FIGURE 12 — Average Lamp Current vs. VBRITE Voltage
(per Lamp)
2) By making a resistor value change on the module. If this
option is preferrable, please contact the factory for applica-
tion assistance.
atthesedimminglevels. Atverylowbrightnesslevels,evenverysmall
amountsofnoiseontheVBRITE linecancauseflickeronthedisplay,so
specialcaremustbegiventogrounding,filteringandshieldingthe
inverterfromthedigitallogicandclock.
Both methods discussed will provide a lower duty cycle
operation than is necessary in a 100:1 dimming application.
Carefulconsiderationshouldbemadewithregardstodisplayquality
FAILSAFE FEATURE FOR MULTIPLE LAMP OPERATIONS
Our multi-output inverters are designed to keep your application
operating at near normal brightness in the event that a lamp fails.
Thisallowsthedisplaytoremain"on-line"untillampreplacement
is convenient.
Linfinity "parallels" the lamps so that if any lamps break, most
of the current is added to the remaining good lamps. CCFLs will
respondwithmorebrightnessforaperiodoftime. Operatingtime
in this mode will be a function of the lamps age but should be
typically in the order of hundreds of hours.
Lamps
This operating characteristic can provide adequate display
performance for a limited, but useful period of time. Shortening
of the lamp life in this mode is typically not a concern as it is
recommended thatall lamps in a display be replaced at the same
time.
IS
RangeMAX INVERTERS
Also available in Single
OutputLXM1611-01,
FIGURE 13 — Quad Output Stage
LXM1612-xx-xx andDual
OutputLXM1621-xx versions
for multiple lamp applications.
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.
Copyright © 1999
Rev. 0.7 12/99
11
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