MICROSEMI LXMG1930-28-01

LXMG1930-28-0x
3-String 5W LED Backlight Boost Driver Module
®
TM
P RODUCTION D ATASHEET
DESCRIPTION
Precision current mirror circuitry
typically provides for 1% percent string to
string matching at the rated output current.
The magnitude of the string current is
easily programmed, in 5mA steps through
an on board DIP switch.
The LXMG1930-28-0x includes over
voltage protection (OVP), and short and
open LED protection. If one string opens,
its current sink will be disabled and the
other strings will continue to operate
normally. Likewise if one or several LEDs
in a string short it will continue to function
with no adverse affect on the other strings.
With the use of an external thermistor the
module can provide LED current fold back
in an over temperature situation.
The module comes in a small form
factor PCB and uses an 8 pin input and one
of three output connectors.
• Drives Up To 3 String LED Panels
• Strings Can Be Combined For
Higher Current
• Wide Input Voltage 4.75V-28V
• String Voltage Up To 35V
• LED String Current Programmable
in 5mA Steps from 15mA to 50mA
For Matching Various Panel
Requirements
• 1% Typical String-to-String
Current Matching
• Analog Dimming Provides For a
10:1 Ratio
• Supports Multiple Methods Of
Dimming Such As DC Voltage,
PWM Signal and Potentiometer
• Output Over Voltage Protection
• LED Over Temperature Protection
Input
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LXMG1930-28-0x module is a boost
white LED driver for medium size LCD
LED backlight panels. It is designed to
drive up to three strings of LEDs to a
maximum of 35V at up to 50mA per string.
The module consists of a boost
converter and three programmable 15 to 50
mA precision current sinks. It is designed
to work over a wide input voltage range
(4.75V to 28V) providing maximum
flexibility. However the converter is a
boost only design requiring the input
supply voltage to not exceed the output
LED string voltage.
The module provides a dimming input:
BRITE_A which adjusts the LED display
brightness by controlling the amplitude of
the LED string current.
The BRITE_A input is very flexible
and can be controlled by a PWM signal,
the application of a DC control voltage or
use of a potentiometer tied as a rheostat.
KEY FEATURES
APPLICATIONS
• Medium Size White LED Backlight
LCD Displays
• Portable Instrumentation Displays
• Medical Instrument Displays
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
Patents Pending
PRODUCT HIGHLIGHT
LXMG1930-28-01
Wide Input
Voltage Range
4.75V to 28V
CN4
Drives Up To Three
String LED Panels. LED
String Voltage up to 35V
CN1
X
SW4
4
Precision
String-to-String Current
Matching
ON
SW3
3
Externally
Programmable LED
String Current From
15mA to 50mA in
5mA Steps
PWM Signal
Supports Multi-Method
Analog Dimming
LXMG1930-28-0x
Potentiometer
SW2
2
DC Voltage
Source
SW1
1
DIMMING INPUT:
Analog – Current Amplitude
Dimming
ORDER INFORMATION
Part Number
LXMG1930-28-01
LXMG1930-28-03
LXMG1930-28-04
Copyright © 2009
Rev. 1.1, 2009-11-25
Input Connector
Output Connector
Molex 53261-0871 or equivalent
Molex 53261-0471 or equivalent
Hirose DF19G-8P-1H or equivalent
Kyocera 04-6298-006-000-883+ or equivalent
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 1
LXMG1930-28-0x
3-String 5W LED Backlight Boost Driver Module
®
TM
P RODUCTION D ATASHEET
ABSOLUTE MAXIMUM RATINGS
Note: 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.
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Input Voltage (VIN)................................................................................................................................................. -0.3V to 30V
Input Power ...................................................................................................................................................................... 6.2W
Output String Current ....................................................................................................................... 53mA (Internally Limited)
Output String Voltage .......................................................................................................................... 38V (Internally Limited)
Output Power ................................................................................................................................................................... 5.5W
Input Signal Voltage (ENABLE Input).................................................................................................................... -0.3V to 30V
Input Signal Voltage (OT)........................................................................................................................................ -0.3V to 5V
Input Signal Voltage (BRITE_A).............................................................................................................................. -0.3V to 6V
Ambient Operating Temperature, zero airflow ....................................................................................................-30°C to 80°C
Storage Temperature Range ..............................................................................................................................-40°C to 85°C
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, might not function optimally.
Parameter
Input Supply Voltage Range
Linear BRITE_A Control Input Voltage Range
LED String Voltage
Each Cathode Sink Current
Operating Ambient Temperature Range
Symbol
Min
R.C.
Max
Units
VIN
4.75
12
28
V
VBRITE_A
0.2
2.2
V
VLED
VIN
35*
V
CSISINK
15
50
mA
TA
-30
75
°C
* Input supply voltage should not exceed LED string voltage as this will result in excessive power dissipation in the module.
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the recommended operating condition and ambient temperature of 0°C to
60°C except where otherwise noted; VIN = 4.75V; BRITE_A = Open; ENABLE = VIN; DIP-SW1~3 = ON; OT = open
Parameter
Symbol
Test Conditions / Comment
VIN
Sleep Current
IIN(MIN)
ENABLE = 0V
Supply Current
IRUN5
VIN = 5V; VLED = 31.2V, ILED = 50mA; 3 Strings
Supply Current
IRUN12
VIN = 12V; VLED = 31.2V, ILED = 50mA; 3
Strings
Supply Current During Fault
Timeout
IFAULT
Open All Output Strings Fault Timeout
Estimated Efficiency
η
VIN = 12V; VLED = 31.2V, ILED = 50mA; 3
Strings
Typ
Max
Units
4.75
12
28
V
20
100
µA
1.5
A
0.5
0.6
A
6
10
mA
80
85
%
Logic
ENABLE Input Low
Voltage
ENABLE Input Hi Voltage
ENABLE VL
ENABLE VH
DIP-SW1~3 = ON
2.0
0.8
V
VIN
V
2.2
V
DIMMING
BRITE_A voltage for Full
Bright
Copyright © 2009
Rev. 1.1, 2009-11-25
1.8
VBRITE_A
2.0
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 2
LXMG1930-28-0x
Input Voltage
Min
LXMG1930-28-0x
®
TM
3-String 5W LED Backlight Boost Driver Module
P RODUCTION D ATASHEET
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the recommended operating condition and ambient temperature of 0°C to
60°C except where otherwise noted; VIN = 4.75V; BRITE_A = Open; ENABLE = VIN; DIP-SW1~3 = ON; OT = open
Symbol
Min
Typ
Max
Units
POT
400
500
600
kΩ
fBRITE_A
100
25000
Hz
BRITE_A PWM Voltage
VBRITE_A-PWM
2.5
5.5
V
BRITE_A Sink Current
IBRITE_A
Potentiometer Dimming on
BRITE_A
PWM Frequency Range
for BRITE_A
Output Current Dim Range
(Analog Dimming)
Test Conditions / Comment
BRITE_A = 0V
12
µA
ILED = 50mA, BRITE_A = 0V Versus BRITE_A
> 2.2V
10
RATIO
LED Current On Rise Time
TCS_Rise
200
ns
LED Current Off Fall Time
TCS_Fall
400
ns
15
V
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Parameter
Device Protection
LED Short Protection
Threshold
VcsSD
Voltage at CSx pin that latches off its
respective string.
CS Pin Over-Voltage Limit
VCSOV
Voltage at CSx pin that clamps Anode Output
23
Combination of DIP Switch1~3 ON/OFF
15
25
27
V
50
mA
LED Current Sink Outputs
LED DC Current
Programming Range
ICS
LED DC Current
ICSMIN
VDIP-SW1~3 = OFF
14.25
15
15.75
mA
LED DC Current
ΔICSA
Delta current SW1~3 = OFF to DIP-SW1= ON
4.75
5
5.25
mA
LED DC Current
ΔICSB
Delta current SW1~3 = OFF to DIP-SW2= ON
9.5
10
10.5
mA
LED DC Current
ΔICSC
Delta current SW1~3 = OFF to DIP-SW3= ON
19
20
21
mA
LED DC Current
ICSMAX
VDIP-SW1~3 = ON
47.5
50
52.5
mA
2
%
Current Matching Between
Strings.
VCSX = 0.8V to 5V
-2
Regulated CS Pin Voltage
At the lowest CS pin, ICSX = 50mA;
DIP- SW1~3 = ON
0.5
Rated LED current
VIN
0.9
V
LED String Voltage
LED String Voltage
VLED
35
V
LED Panel Thermal Protection
VOT
OT Sink Current
IOT
Copyright © 2009
Rev. 1.1, 2009-11-25
VOT
OT = 0V
1.47
V
1.8
V
240
µA
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 3
LXMG1930-28-0x
LED Over Temperature
Shut Down Threshold
Over Temperature
Recovery Voltage
LXMG1930-28-0x
®
TM
3-String 5W LED Backlight Boost Driver Module
P RODUCTION D ATASHEET
Name
Pin #
Description
CN1 (Molex 53261-0871) for LXMG1930-28-0x
CN1-1
CN1-2
CN1-3
CN1-4
VIN
GND
CN1-5
ENABLE
CN1-6
OT
CN1-7
BRITE_A
CN1-8
NC
Main Input Power Supply 4.75V to 28V
Power Supply Return
ON/OFF Control. (ENABLE = 0V = OFF, ENABLE = 2V = ON)
Operating Temperature Detection Input. A Thermistor Usually Is Connected From This Pin To
Ground.
Analog Dimming Input. BRITE_A 0~2.2V→Io 10%~100%. 100Hz<f <25kHz, 3.3V PWM and
500kohms Rheostat are Equivalent Dimming Methods.
No Connect, Leave This Pin Open
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FUNCTIONAL PIN DESCRIPTION
CN2 (Kyocera 04-6298-006-000-883+) for LXMG1930-28-04 (Please verify proper polarity of FPC to panel backlight connection)
CN2-1
Anode
CN2-2
CSA
CN2-3
Anode
CN2-4
CSB
CN2-5
Anode
CN2-6
CSC
Common LED High Side Drive Voltage
Channel A Cathode Sink Driver
Common LED High Side Drive Voltage
Channel B Cathode Sink Driver
Common LED High Side Drive Voltage
Channel C Cathode Sink Driver
CN3 (Hirose DF19G-8P-1H) for LXMG1930-28-03
CN3-1
Anode
Common LED High Side Drive Voltage
CN3-2
CSA
CN3-3
Anode
CN3-4
CSB
CN3-5
Anode
CN3-6
CSC
CN3-7
NC
No Connect
CN3-8
NC
No Connect
Channel A Cathode Sink Driver
Common LED High Side Drive Voltage
Channel B Cathode Sink Driver
Common LED High Side Drive Voltage
Channel C Cathode Sink Driver
LXMG1930-28-0x
CN4 (Molex 53261-0471) for LXMG1930-28-01
CN4-1
Anode
CN4-2
CSA
Channel A Cathode Sink Driver
CN4-3
CSB
Channel B Cathode Sink Driver
CN4-4
CSC
Channel C Cathode Sink Driver
Copyright © 2009
Rev. 1.1, 2009-11-25
Common LED High Side Drive Voltage
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 4
LXMG1930-28-0x
®
TM
3-String 5W LED Backlight Boost Driver Module
P RODUCTION D ATASHEET
DIP SWITCH LED STRING CURRENT SETTINGS
SW2 (10mA)
SW3 (20mA)
OFF
OFF
ON
LED String Current
Notes
OFF
15mA
Minimum String current
OFF
OFF
20mA
OFF
ON
OFF
25mA
ON
ON
OFF
30mA
OFF
OFF
ON
35mA
ON
OFF
ON
40mA
OFF
ON
ON
45mA
ON
ON
ON
50mA
1
2
Maximum String Current
UP - ON
ON
DIP Switch
S1
SW4 (not used)
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SW1 (5mA)
3
4
DOWN - OFF
Example shows S1 programmed for 25mA LED String Current
LXMG1930-28-0x
Copyright © 2009
Rev. 1.1, 2009-11-25
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 5
LXMG1930-28-0x
3-String 5W LED Backlight Boost Driver Module
®
TM
P RODUCTION D ATASHEET
SIMPLIFIED BLOCK DIAGRAM
LED High Side Drive Voltage
VIN
ENABLE
BRITE_A
CSA
1
2
CSB
3
4
CSC
5
6
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+5V
CN2
Control
Circuitry
+5V
CSA
1
2
CSB
3
4
CSC
20.5k
5
6
7
8
OT
CN3
GND
ANODE
CSA
1
2
CSB
3
4
CSC
CN4
SW1 SW2 SW3
DIP Switch
MECHANICAL DRAWING
3.6mm
0.142in.
GROUNDED MOUNTING
HOLE 3.18MM ±.08 DIA.
49.88mm ±0.2
6.0 mm MAX
0.236 in.
1.96in.
CN4 CN2
CN1
27.9 mm
1.098 in.
X
21.08 mm ±0.2
0.83 in.
2
SW3
3
SW4
4
3.22mm
0.127in
S1
53.48mm ±0.2
2.11in.
69 mm
CN3
MOUNTING HOLE
3.18MM ±.08 DIA.
1.0 mm
0.039 in.
2.72in.
Dimensions are in millimeters (inches are for reference only)
PCB tolerances ± 0.5mm , M3 recommended mounting screws
Weight: (8g) typ.
Copyright © 2009
Rev. 1.1, 2009-11-25
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 6
LXMG1930-28-0x
1
SW2
ON
SW1
LXMG1930-28-0x
®
TM
3-String 5W LED Backlight Boost Driver Module
P RODUCTION D ATASHEET
APPLICATION INFORMATION
4.75V to 28V
The LED string current and therefore the brightness may be
controlled by the BRITE_A input. The typical dimming
range using the BRITE_A input alone is 10:1.
ƒ
The BRITE_A input may come from a voltage output DAC
or other voltage source, a 500k digital or manual pot, or a
PWM signal in the range of 100 Hz to 25 kHz. The module
contains an internal 422k pull-up to typically 5V to provide
bias if using a pot. Logic levels may be used up to 5V,
however the inverter will reach maximum current at less than
100% duty cycle. This can be calculated as approximately
2.2V divided by the logic high voltage level; with 3.3V logic
level this corresponds to about 66% duty cycle for maximum
string current.
ƒ
If you need to turn the module ON/OFF remotely, connect to
TTL logic signal to the ENABLE input.
ƒ
It is to be noted that although the module provides for a wide
input voltage range 4.75V to 28V it is designed as a boost
only converter. Therefore the input voltage should not
exceed the LED string voltage.
ƒ
Use of an external thermistor connected from OT pin to
ground will provide over temperature protection (see figure
2). The module can provide for the gradual scaling back of
LED string current until it is completely shut off based on the
voltage level impressed on the OT input. When the voltage
on the OT pin decreases below 2.48V the string current will
begin to decrease until it is completely shut off when OT
reaches 1.47V. This corresponds to a thermistor value of
about 8542 ohms at string current shutdown.
ƒ
As an example using a 100k (at 25°C) NTC thermistor with a
B Constant of 4250 will provide a thermal profile where the
module will begin to scale back the LED string currents at a
temperature (as measured by the thermistor) greater than
60°C and shut down the string current if the temperature
exceeds 85°C.
ƒ
Although the module provides open circuit string protection,
if the common LED high side drive voltage (Anode) is
directly shorted to ground this will result in damage to the
fuse and possible damage to the Schottky diode. Likewise if
any of the low side current sink drivers (CSx) are directly
shorted to ground it will result in damage to the fuse,
Schottky diode and possibly the LED string.
VIN
Voltage Source,
DAC, or
Potentiometer
ANODE
CSA
LXMG1930-28-0x
0V to 2.2V
ANODE
CSB
BRITE_A
500k
ANODE
CSC
ENABLE
GND
Figure 1
+5V
20.5k
OT (pin 6)
VRT
RT
NTC
5
VRT = 20.5k + R x RT
T
Figure 2
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ƒ
LXMG1930-28-0x
Copyright © 2009
Rev. 1.1, 2009-11-25
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 7
LXMG1930-28-0x
TM
®
3-String 5W LED Backlight Boost Driver Module
P RODUCTION D ATASHEET
NOTES
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LXMG1930-28-0x
PRODUCTION DATA – Information contained in this document is proprietary to
Microsemi and is current as of publication date. This document may not be modified in
any way without the express written consent of Microsemi. Product processing does not
necessarily include testing of all parameters. Microsemi reserves the right to change the
configuration and performance of the product and to discontinue product at any time.
Copyright © 2009
Rev. 1.1, 2009-11-25
Microsemi
Analog Mixed Signal Group
11861 Western Avenue, Garden Grove, CA. 92841, 800-877-6458, 714-898-8121, Fax: 714-893-2570
Page 8