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LIN DOC #: 1596
LXM1596-01
WIDE INPUT CCFL INVERTER MODULES
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DESCRIPTION LXM1596-01 CCFL (cold cathode florescent lamp) Inverter Modules are specifically designed for driving LCD back light lamps in applications where dimmability, ultrahigh efficiency, high light output, low noise emissions, reliable fail safe design, and small form factors are critical parameters. Both monochrome and color displays are supported. The modules convert unregulated DC voltage from the system battery or AC adapter directly to high-frequency, highvoltage sine waves required to ignite and operate CCFL lamps. The module design is based on a proprietary Linfinity IC that provides important new performance advances. Remarkable improvements in efficiency and RF emissions result from its single stage resonant inverter featuring a patent pending Current Synchronous, Zero Voltage Switching (CS-ZVS) topology. CS-ZVS produces nearly pure sine wave currents in the lamp enabling maximum light delivery while reducing both conducted and radiated noise. This topology simultaneously performs three tasks consisting of line voltage regulation, lamp current regulation, and lamp dimming in a single power stage made up of one pair of low loss FET's. The FET's drive an LC resonant circuit that feeds the primary of a high voltage transformer with a sinusoidal voltage. Required L and C values in the resonant circuit are such that very low loss components can be used to obtain higher electrical efficiency than is possible with previous topologies. The half bridge LXM1596-01 is optimized to efficiently operate with up to 4 watt lamps over the full 7V to 30V input voltage range. The modules are equipped with a dimming input that permits full range brightness control from an external potentiometer, and a sleep input that reduces module power to a few microwatts in shut down mode. All modules feature output open and short circuit protection.
K E Y F E AT U R E S
s 15 to 30% More Light Output s Closed Loop, Fully Regulating Design s 7V To 30V Input Voltage Range s Versatile Brightness Control Input s 3 MicroAMP Sleep Current s Output Short Circuit Protection And Automatic Over-Voltage Limiting s 8mm Max. Height, Narrow Footprints s Single Sided PCB Is Self Insulating
APPLICATIONS
s Notebook And Sub-Notebook Computers s Personal Digital Assistants s Portable Instrumentation s Automotive Displays s Desktop Displays s Airline Entertainment Centers
BENEFITS
s Ultra-High Efficiency, Line Voltage Regulation And Sleep Mode Extend Computer Battery Life s Cool Operation PermitS Close Proximity To LCD Panel Without Display Distortion s Smooth, Full-Range Brightness Control Gives Your Product A High Quality Image s Low EMI / RFI Design Minimizes Shielding Requirements s Narrow, Low-Profile Standard Modules Fit Into Most LCD Enclosures s Single Sided PCB Saves Expensive High Voltage Insulating Tapes
IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.
PRODUCT HIGHLIGHT
BACKLIGHT INVERTER LIGHT OUTPUT EFFICIENCY COMPARISON
50 45 40 Eff (Nits / Watts) 35 30 25 20 15 10 5 0 Computer 1 Computer 2 Computer 3
Linfinity Stock
MODULE ORDER INFO
7V - 30V INPUT LXM1596-01
Copyright (c) 1998 Rev. 0.7 4/98
LINFINITY MICROELECTRONICS INC.
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
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PRODUCT DATABOOK 1996/1997
WIDE INPUT CCFL INVERTER MODULES
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LXM1596-01
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A B S O L U T E M A X I M U M R AT I N G S
(Note 1)
Input Supply Voltage (VIN) ................................................................................................................................................................................ -0.3V to 30V Output Voltage, no load ........................................................................................................................................................ Internally Limited to 1900VRMS Output Current ......................................................................................................................................................................... 8.0mARMS (Internally Limited) Output Power .................................................................................................................................................................................................................. 4.2W Input Signal Voltage, (SLEEP and BRITE Inputs) ............................................................................................................................................ -0.3V to 6.5V Ambient Operating Temperature, zero airflow .................................................................................................................................................. 0C to 60C 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 the 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. Parameter
Input Supply Voltage Output Power Brightness Control Input Voltage Range Lamp Operating Voltage Lamp Current - Full Brightness Operating Ambient Temperature Range
Symbol
VIN PO VBRITE VLAMP IOLAMP TA
Recommended Operating Conditions Min. R.C. Max.
7 0.8 240 0 12 2.5 500 5 30 4.0 2.5 650 7 60
Units
V W V VRMS mA RMS C
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, these specifications apply over the recommended operating conditions and 25C ambient temperature for the LXM1596.
Parameter Output Pin Characteristics
Full Bright Lamp Current Minimum Lamp Current Lamp Start Voltage Operating Frequency
Symbol
IL (MAX) IL (MIN) VLS fO IBRITE VC VC VIH VIL IIN V REF IREF IIN (MIN)
Test Conditions
VBRITE = 2.5 V DC, SLEEP = Logic High VBRITE = 0.8 V DC, SLEEP = Logic High 0C < TA < 60C VBRITE = 2.5VDC, SLEEP = Logic High, VIN = 12V VBRITE = 0V DC IO (LAMP) = 100% IO (LAMP) = 50%
Min.
6.2 1300
LXM1596 Typ. Max.
6.6 2.6 50 -200 2.5 1.25 -1000 2.6 7.0
Units
mA mA RMS VRMS KHz nADC VDC VDC VDC VDC ADC VDC ADC ADC %
Brightness Control
Input Current Input Voltage for Max. Lamp Current Input Voltage for 50% Lamp Current
2.4
SLEEP Input
Input Logic 1 Input Logc 0 Input Current 2.2 0 VSLEEP = 0 - 5VDC 0 < IREF < 500A 2.40 500 50 2.50 5.5 0.8 100 2.60
Voltage Reference
Output Voltage Output Current
Power Characteristics
Sleep Current Electrical Efficiency (calculated values)
VIN = 5VDC , SLEEP = Logic 0 LXM1596, VIN = 12VDC, IO (LAMP) = 5mARMS
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Copyright (c) 1998 Rev. 0.7 4/98
PRODUCT DATABOOK 1996/1997
WIDE INPUT CCFL INVERTER MODULES
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FUNCTIONAL PIN DESCRIPTION
Conn. CN1
CN1-1 CN1-2 CN1-3 CN1-4 CN1-5 CN1-6
Pin
VIN N.C. GND SLEEP
Description
Input voltage. (+7 to +30VDC ) No Connect. Power supply return. Logical high on this pin enables inverter operation. Logical low removes power from the module and the lamp. A floating input is sensed as a logical low and will disable inverter operation. If not used, connect SLEEP through a 33k resistor to VIN or directly to any voltage between 2.5 and 5.5V. Brightness control input. Apply 0.8 to 2.5 volts DC to control lamp brightness. Lamp current varies linearly with input voltage. 2.5V gives maximum brightness. Reference Voltage Output. 2.5V @ 500A max. For use with external dimming circuit.
CN1-7 CN1-8
BRITE VREF
CN2
CN2-1 CN2-2 LAMP LO LAMP HI High voltage connection to low side of lamp. Connect to lamp terminal with longer lead length. Do not connect to ground. High voltage connection to high side of lamp. Connect to lamp terminal with shortest lead length. Do not connect to ground. MECHANICAL OUTLINE
.40 (10.16) 4.76 (120.9) 4.05 (102.9) 1-1 .83 (21.08) 1-8 .21 (5.33) .500 (12.7) 2-2 2-1
Connector CN-1
0.125 (3.18) Diameter Hole, 2 places No other holes on board.
Connector CN-2 Warning!! High Voltage Present
.315 Max. (8)
.031 (0.8) All dimensions in inches (mm)
Connectors: CN-1 = MOLEX 53261-0890 CN-2 = JST SM02(8.0) B-BHS-TB
Recommended Mate: Pins: 50079-8100*, Housing: 51021-0800
* Loose (-8000, Chain) Recommended #26 AWG wiring
Pins: 5BH-001T-P0.5, Housing: BHR-03VS-1
Note: All samples are equipped with connector mates and cable.
Copyright (c) 1998 Rev. 0.7 4/98
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CONNECTION DIAGRAM
CMOS or TTL gate From Power Management Logic
SLEEP VREF R1 100k R2 51k BRITE
VIN
LAMP HI CFL TUBE
Lamp Current (%) =
VBRITE x 100 VREF
LXM1596-01
LAMP LO GND
R1 = 100k typical, 5k minimum R2 = Value optional to determine lowest brightness setting R2 = 0.5 R1 minimum
Longest Lead
FIGURE 1 Recommended Connection Diagram EFFICIENCY MEASUREMENT SETUP INTRODUCTION The best method for evaluating high voltage, high frequency inverters is by directly measuring light output versus power input. This method is highly recommended when evaluating inverter modules. The following sections outline the recommended method for testing these modules. EQUIPMENT REQUIRED 1) 2) 3) 4) 5) 6) Two DVM's with 0.1% or better accuracy. A lab power supply. (0 - 20V, 0 - 2A) The target notebook or LCD panel. A Tektronix J1803 Luminance Head. A Tektronix J17 Luminance Color Photometer. A non-contact infrared temperature sensor (i.e. Fluke 80T-IR) with a mV meter. the end of the 30 minute period read the light output in cd/m 2 (1 cd/m2 = 1 Nit), as well as input voltage and current. Typical applications require about 70 to 100 Nits out of the screen. With the temperature probe record the temperature rises of critical components such as the high voltage transformer and the inductor. The light output efficiency of the module can be calculated by the following equation: Eff = Nits Light Output (in Nits) = Watt VIN (DC) * IIN (DC)
MEASUREMENT SETUP Figure 2 shows the connection diagram for light output measurements. The photometer luminance head (J1803) is positioned directly in the center of the LCD screen. For best results open an application such as the Paintbrush program and choose the maximized view so that the entire screen is "white". After application of the power to the CCFL wait at least 30 minutes to allow for the lamp and light output to stabilize. At
For competitive evaluation with another module from Linfinity or another manufacturer repeat the above steps for the second module. After taking the data on the second module, compare the temperature rises on the transformer and inductors. The main figure of merit comparison is done between the two Eff numbers as follows: Percent More Efficient = Eff1 - Eff 2 Eff 2 * 100
The result of the above shows how much more efficient module #1 is than module #2.
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Copyright (c) 1998 Rev. 0.7 4/98
PRODUCT DATABOOK 1996/1997
WIDE INPUT CCFL INVERTER MODULES
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EFFICIENCY MEASUREMENT SETUP
(continued)
DC Power Supply
DC Amp Meter
DC Volt Meter
PIN = VDC * IDC
Sleep Control = Logic "1"
Dimming Control
Inverter Module
CCFL
J1803 Luminance Head
J17 Photometer
FIGURE 2 Light Output Measurement Setup
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 (c) 1998 Rev. 0.7 4/98
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