P
RELIMINARY
D
ATASHEET
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
Copyright
2002
Rev. 0.5a, 2003-01-20
WWW
.
Microse
m
i
.
CO
M
P
P
a
a
n
n
e
e
l
l
M
M
a
a
t
t
c
c
h
h
TM
TM
LXM1644-12-61
12V Quad 6W CCFL Programmable Inverter Module
I N T E G R A T E D P R O D U C T S
D E S C R I P T I O N
The LXM1644-12-61 is a Quad 6W
Output Direct DriveTM CCFL (Cold
Cathode Fluorescent Lamp) Inverter
Module specifically designed for driving
LCD backlight lamps. It is ideal for
driving typical 12.1" to 18.1" TFT panels.
The modules are available with a
dimming input that permits brightness
control from either a DC voltage source or
a PWM signal or external Potentiometer.
The maximum output current is externally
programmable over a range of 10 to 16mA
in 1mA steps to allow the inverter to
properly match to a wide array of LCD
panel lamp current specifications.
LXM1644 modules unlike the
LXM1643 series does not provide wide
range `burst' mode dimming, rather
dimming is provided by amplitude control
of the output current waveform, this limits
the potential dim range to typically less
than 5:1.
For applications not requiring wide
range dimming, amplitude control results
in lower ripple on the input supply and
reduced potential transient noise
generation. Many STN type panels are
particularly well suited for current
amplitude dimming.
The modules convert DC voltage from
the system battery or AC adapter directly
to high frequency, high-voltage waves
required to ignite and operate CCFL
lamps.
The LXM1644-12-61 inverter is in-
tended for panel assemblies where lamp
pairs share close proximity with one
another and a common return (low side)
wire.
Other benefits of this new topology
are stable fixed-frequency operation,
secondary-side strike-voltage regulation
and both open/shorted lamp protection
with fault timeout.
IMPORTANT:
For the most current data and a panel to inverter cross reference, consult
MICROSEMI
's website:
http://www.microsemi.com
K E Y F E A T U R E S
Externally Programmable
Maximum Output Current
Easy to Use Brightness
Control
Analog Current Amplitude
Dimming Method
Output Open/Short-Circuit
Protection and Timeout
Fixed Frequency Operation
Rated From -20 to 70C
UL 60950 E175910
A P P L I C A T I O N S
High Brightness Displays
Desktop Displays
Industrial Display Controls
B E N E F I T S
Compact, Low Profile
Design
Programmable output
current allows inverter to
mate with a wide variety of
LCD panel's specifications
P R O D U C T H I G H L I G H T
Selectable Maximum Output Current 10mA to 16mA
RMS
DC Voltage
Source
Potentiometer
PWM
Signal
Universal Dimming Input PWM, VDC, or
P A C K A G E O R D E R I N F O
ART
N
UMBER
O
UTPUT
C
ONNECTORS
I
NVERTER
M
ATES
D
IRECTLY TO
P
ANEL
C
ONNECTORS
LXM1644-12-61 Two JST SM04(4.0)B-BHS-1-TB
JST BHR-04VS-1
L
L
X
X
M
M
1
1
6
6
4
4
4
4
-
-
1
1
2
2
-
-
6
6
1
1
P
RELIMINARY
D
ATASHEET
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
Copyright
2002
Rev. 0.5a, 2003-01-20
WWW
.
Microse
m
i
.
CO
M
P
P
a
a
n
n
e
e
l
l
M
M
a
a
t
t
c
c
h
h
TM
TM
LXM1644-12-61
12V Quad 6W CCFL Programmable Inverter Module
I N T E G R A T E D P R O D U C T S
A B S O L U T E M A X I M U M R A T I N G S
( N O T E 1 )
Input Signal Voltage (V
IN1
).....................................................................................................................................-0.3V to 15V
Input Power ....................................................................................................................................................................... 30W
Output Voltage, no load ............................................................................................................ Internally Limited to 2000V
RMS
Output Current (each output) ......................................................................................................9.5mA
RMS
(Internally Limited)
Output Power (each output) ............................................................................................................................................. 6.0W
Input Signal Voltage ( SLEEP Input)..................................................................................................................... -0.3V to V
IN1
Input Signal Voltage (BRITE) ...............................................................................................................................-0.3V to 5.5V
Ambient Operating Temperature, zero airflow.....................................................................................................-20C to 70C
Operating Relative Humidity, non-condensing ................................................................................................................ 90%
Storage Temperature Range...............................................................................................................................-40C to 85C
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 specified
terminal.
R E C O M M E N D E D O P E R A T I N G C O N D I T I O N S ( 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
Min R.C. Max
Units
Input Supply Voltage Range (Fully Regulated
Lamp Current)
10.8 12 13.2
Input Supply Voltage Range (Functional)
V
IN1
10.2 12 13.8
V
Output Power (each lamp)
P
O
5.0
6.0* W
Linear BRITE Control Input Voltage Range
V
BRT_ADJ
0.65 to 0.9
2.0
V
Lamp Operating Voltage
V
LAMP
530 625 720 V
RMS
Lamp Current (Each pair, Full Brightness)
I
OLAMP
10 16
mA
RMS
Operating Ambient Temperature Range
T
A
-20 70 C
*Total output power must not exceed 12W per lamp pair. Higher voltage lamps may require the maximum output current to be set lower 16mA
The minimum V
BRT ADJ
voltage depends on the panel characteristics, depending on the panel it can vary from 0.65V to 0.9V
E L E C T R I C A L C H A R A C T E R I S T I C S
Unless otherwise specified, the following specifications apply over the recommended operating condition and ambient temperature of
25
C except where otherwise noted.
LXM1644-12-61
Parameter Symbol Test
Conditions
Min Typ Max
Units
OUTPUT PIN CHARACTERISTICS
Full Bright Lamp Current (two lamps)
I
L(MAX)
V
BRT_ADJ
> 2.0V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= Ground, I
SET2
= Ground
9 10 11
mA
RMS
Full Bright Lamp Current (two lamps)
I
L(MAX)
V
BRT_ADJ
> 2.0V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= Ground, I
SET2
= Open
10.8 12 13
mA
RMS
Full Bright Lamp Current (two lamps)
I
L(MAX)
V
BRT_ADJ
> 2.0V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= Open, I
SET2
= Ground
12.8 14 15
mA
RMS
Full Bright Lamp Current (two lamps)
I
L(MAX)
V
BRT_ADJ
> 2.0V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= Open, I
SET2
= Open
14.7 16 17
mA
RMS
Output Current pair of Lamps to pair of
Lamps Deviation
I
LL%DEV
V
BRT_ADJ
> 2.0V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= Open, I
SET2
= Open
3
10
%
Min. Average Lamp Current
(each output)
I
L(MIN)
V
BRT_ADJ
0.5V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
DC
I
SET1
= I
SET2
= Ground
5.5
mA
RMS
Lamp Start Voltage
V
LS
-20C
<
T
A
< 70C, V
IN1
> 10.8V
DC
1500
1650
V
RMS
Operating Frequency
f
O
V
BRT_ADJ
= 2.5V
DC
,
SLEEP
> 2.0V, V
IN1
= 12V
69 72 75 kHz
The inverter is capable of a lower output current than may be recommended by the panel manufacturer. It is the user's responsibility to set the minimum brightness
(BRITE) input at or above the panel specification for minimum current.
E
E
L
L
E
E
C
C
T
T
R
R
I
I
C
C
A
A
L
L
S
S
P
RELIMINARY
D
ATASHEET
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
Copyright
2002
Rev. 0.5a, 2003-01-20
WWW
.
Microse
m
i
.
CO
M
P
P
a
a
n
n
e
e
l
l
M
M
a
a
t
t
c
c
h
h
TM
TM
LXM1644-12-61
12V Quad 6W CCFL Programmable Inverter Module
I N T E G R A T E D P R O D U C T S
E L E C T R I C A L C H A R A C T E R I S T I C S ( C O N T I N U E D )
Unless otherwise specified, the following specifications apply over the recommended operating condition and ambient temperature of
25
C except where otherwise noted.
LXM1644-12-61
Parameter Symbol Test
Conditions
Min Typ Max
Units
BRITE INPUT
V
BRT_ADJ
= 0V
DC
-300
A
DC
Input Current
I
BRT
V
BRT_ADJ
= 3V
DC
50
A
DC
Minimum Input for Max. Lamp Current V
BRT_ADJ
I
O(LAMP)
= Maximum Lamp Current
2.0
2.05
V
DC
Minimum Input for Min. Lamp Current
V
BRT_ADJ
I
O(LAMP)
= Minimum Lamp Current
0.65*
V
DC
SLEEP INPUT
RUN Mode
SLEEP
V
2.0
V
IN1
V
DC
SLEEP Mode
SLEEP
V
-0.3
0.8
V
DC
SET
1,2
INPUT
SET
1,2
Low Threshold
V
L
0.4 V
Input Current
I
SET
V
SET
0.4V
-300
A
POWER CHARACTERISTICS
Sleep Current
I
IN(MIN)
V
IN1
= 12V
DC
,
SLEEP
< 0.8V
0.0 10 30 A
DC
Run Current
I
RUN
V
IN1
= 12V
DC
,
SLEEP
2.0V, I
SET1
= Open
I
SET2
= Ground, V
LAMP
= 625V
RMS
1750 mA
DC
Efficiency
V
IN1
= 12V
DC
,
SLEEP
2.0V, I
SET1
= Open
I
SET2
= Ground, V
LAMP
= 625V
RMS
85 %
* The Inverter is capable of a lower output current than may be recommended by the panel manufacturer. It is the user's responsibility to set the minimum brightness
(BRITE) input at or above the panel specification for minimum current. This is likely greater than the 0.65V minimum input.
F U N C T I O N A L P I N D E S C R I P T I O N
C
ONN
P
IN
D
ESCRIPTION
CN1
(Molex 53261-1290) Mates with 51021-1200 housing, 50079-8100 pins. Mates with LX9508 input cable assembly
CN1-1,2,3 V
IN1
Main Input Power Supply (10.8V < V
IN1
< 13.2V)
CN1-4,5,6 GND Power
Supply
Return
CN1-7
AGND
Analog Signal Ground
CN1-8 NC
No
Connect
CN1-9
SLEEP
ON/OFF Control. (0V <
SLEEP
< 0.8 = OFF,
SLEEP
>= 2.0V = ON
CN1-10
BRITE
Brightness Control (0.65V to 2.0V). 2.0V
DC
gives maximum lamp current.
CN1-11 SET
1
SET
1
MSB Connecting this pin to ground decreases the output current (see Table 1)
CN1-12 SET
2
SET
2
LSB Connecting this pin to ground decreases the output current (see Table 1)
CN2, CN3
(JST SM04(4.0)B-BHS-1-TB)
CN2,3-1 V
HI1
High voltage connection to high Side of lamp. Connect to lamp terminal with shortest lead length.
DO NOT
connect to Ground.
CN2,3-2 V
HI2
High voltage connection to high Side of lamp. Connect to lamp terminal with shortest lead length.
DO NOT
connect to Ground.
CN2,3-3 NC Open
Pin
CN2,3-4 V
LO
Connection to low side of lamps. Connect to lamp terminal with longer lead length.
DO NOT
connect to Ground
E
E
L
L
E
E
C
C
T
T
R
R
I
I
C
C
A
A
L
L
S
S
P
RELIMINARY
D
ATASHEET
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
Copyright
2002
Rev. 0.5a, 2003-01-20
WWW
.
Microse
m
i
.
CO
M
P
P
a
a
n
n
e
e
l
l
M
M
a
a
t
t
c
c
h
h
TM
TM
LXM1644-12-61
12V Quad 6W CCFL Programmable Inverter Module
I N T E G R A T E D P R O D U C T S
T A B L E 1
OUTPUT CURRENT SETTINGS (TWO LAMPS)
SET
1
(Pin 11)
SET
2
(Pin 12)
Nominal Output Current
Open*
Open*
16.0mA
Open*
Ground
14.0mA
Ground
Open*
12.0mA
Ground
Ground
10.0mA
* If driven by a logic signal it should be open collector or open drain only, not a voltage source.
P H Y S I C A L D I M E N S I O N S
Weight: 44g typ
.
Warning
High Voltage Present at
high side of both
Transformers and Output
Connectors
7.40in
188mm
G
ROUNDED
M
OUNTING
H
OLES
3.18
MM
.08 DIA.
1.41in.
36mm
SM04(4.0)B-BHS-1-TB
(JST)
PCB tolerances 0.5mm
0.060in.
1.52mm
0.315in.
8.0mm Max
CN-1
7.16in
182mm
0.15in
4mm
0.15in
4mm
0.15in
4mm
3.70in
94mm
0.23in
6mm
S I M P L I F I E D B L O C K D I A G R A M
LA
M
P
V
LO
V
HI
High Voltage Transformers
I
SENSE
OV
SENSE
V
IN1
OC
SENSE
One of two
LA
M
P
V
HI
Z
Z
Controller and
Transform er
Driver
V
BRITE
SET
1
SET
2
+3V
10K
10K
10K
+3V
+3V
P
P
A
A
C
C
K
K
A
A
G
G
E
E
D
D
A
A
T
T
A
A
P
RELIMINARY
D
ATASHEET
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
Copyright
2002
Rev. 0.5a, 2003-01-20
WWW
.
Microse
m
i
.
CO
M
P
P
a
a
n
n
e
e
l
l
M
M
a
a
t
t
c
c
h
h
TM
TM
LXM1644-12-61
12V Quad 6W CCFL Programmable Inverter Module
I N T E G R A T E D P R O D U C T S
T Y P I C A L A P P L I C A T I O N
LXM1644-12-61
12V
SET
2
GND
V
H2
V
LO
BRITE
V
IN1
SLEEP
SET
1
NC
NC
V
H1
One of
two
Rx*
20K
DAC or
Pot
*Set Rx from 1.8K to 3.9K depending on panel
minimum lamp current requirements
Figure 1
Brightness Control
(Output current set to maximum)
P.W .
10us to 125uS
BRITE
LXM1644-12-61
26% < P.W. < 100% of
period
PW M Signal
from System
Figure 1A
PWM Brightness Control
LXM1644-12-61
SLEEP
BRITE
12V
V
IN1
SET
2
GND
SET
1
One
of two
L L 10.0mA
RMS
L H 12.0mA
RMS
H L 14.0mA
RMS
H H 16.0mA
RMS
L=GND; H=Open
Figure 2
Max Output Current (Two Lamps)
(SET
1
and SET
2
Inputs)
The brightness control may be a voltage output DAC or
other voltage source, a digital pot or 20K manual pot. The
inverter contains an internal 10K pull-up to 3V to bias the
pot, add a 1.8K to 3.9K resistor to set the lower threshold
voltage. A 3.3V Logic Level PWM signal from a micro-
controller may also be used as shown in Figure 1A.
If you need to turn the inverter ON/OFF remotely, connect
to TTL logic signal to the
SLEEP
input.
Connect V
HI
to high voltage wire from the lamp. Connect
V
LO
to the low voltage wire (wire with thinner insulation).
Never connect V
LO
to circuit ground as this will defeat
lamp current regulation. If both lamp wires have heavy
high voltage insulation, connect the longest wire to V
LO
.
This wire is typically white.
Use the SET
1
and SET
2
(see Figure 2) inputs to select the
desired maximum output current. Using these two pins in
combination allows the inverter to match a wide variety of
panels from different manufactures. Generally the best
lamp lifetime correlates with driving the CCFL at the
manufactures nominal current setting. However the SET
1
and SET
2
inputs allow the user the flexibility to adjust the
current to the maximum allowable output current to
increase panel brightness at the expense of some reduced
lamp life.
Although the SET pins are designed such that just leaving
them open or grounding them is all that is needed to set the
output current, they can also be actively set. Using a open
collector or open drain logic signal will allow you to
reduce the lamp current for situations where greater dim
range is required, as an example in nighttime situations. In
conjunction with a light sensor or other timer the panel
could be set to higher brightness (maximum output
current) for daytime illumination and lower brightness
(minimum or typical output current) at nighttime. Since
the dim ratio is a factor of both the burst duty cycle and the
peak output current, using this technique the effective dim
ratio can be increased greater than the burst duty cycle
alone. Conversely the SET inputs could be used to
overdrive the lamp temporarily to facilitate faster lamp
warm up at initial lamp turn on. Of course any possible
degradation on lamp life from such practices is the users
responsibility since not all lamps are designed to be
overdriven.
The inverter has a built in fault timeout function. If the
output return is open (lamp disconnected or broken) or
shorted the inverter will attempt to strike the lamp for
several seconds. After about a second without success the
inverter will shutdown. In order to restart the inverter it is
necessary to toggle the sleep input or cycle the V
IN1
input
supply. In the timeout shutdown mode input drain current
will be about 8mA.
A
A
P
P
P
P
L
L
I
I
C
C
A
A
T
T
I
I
O
O
N
N
PDF 
ZIP