P A T E N T P LIN D O C #: 1598 E N D I N G LXM1598-01 12V CCFL I T H E I N F I N I T E P O W E R O F I N V E R T E R O D U L E S Not Recommended for New Designs N N O VA T I O N DESCRIPTION LXM1598-01 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 radi- M K E Y F E AT U R E S ated 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 LXM1598-01 is optimized to efficiently operate with up to 4 watt lamps over the full 10V to 14V 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. IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com. ■ 15 to 30% More Light Output ■ Closed Loop, Fully Regulating Design ■ 10V To 14V Input Voltage Range ■ Versatile Brightness Control Input ■ 3 MicroAMP Sleep Current ■ Output Short Circuit Protection And Automatic Over-Voltage Limiting ■ 8mm Max. Height, Narrow Footprints APPLICATIONS ■ Notebook And Sub-Notebook Computers ■ Personal Digital Assistants ■ Portable Instrumentation ■ Automotive Displays ■ Desktop Displays ■ Airline Entertainment Centers BENEFITS ■ Ultra-High Efficiency, Line Voltage Regulation And Sleep Mode Extend Computer Battery Life ■ Cool Operation PermitS Close Proximity To LCD Panel Without Display Distortion PRODUCT HIGHLIGHT BACKLIGHT INVERTER LIGHT OUTPUT EFFICIENCY COMPARISON ■ Smooth, Full-Range Brightness Control Gives Your Product A High Quality Image ■ Low EMI / RFI Design Minimizes Shielding Requirements 50 ■ Narrow, Low-Profile Standard Modules Fit Into Most LCD Enclosures 45 Eff (Nits / Watt) 40 35 30 25 20 15 10 5 Linfinity 0 Computer 1 Stock Computer 2 Computer 3 MODULE ORDER INFO 10V - 14V INPUT LXM1598-01 Copyright © 1998 Rev. 0.8a 10/00 LINFINITY MICROELECTRONICS INC. 11861 W ESTERN A VENUE, G ARDEN G ROVE, CA. 92841, 714-898-8121, F AX: 714-893-2570 1 P AT E N T P E N D I N G PRODUCT DATABOOK 1996/1997 LXM1598-01 12V CCFL I N V E R T E R M O D U L E S Not Recommended for New Designs 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 20V 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 .................................................................................................................................................. 0°C to 60°C 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. 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 Symbol Input Supply Voltage Output Power Brightness Control Input Voltage Range Lamp Operating Voltage Lamp Current - Full Brightness Operating Ambient Temperature Range VIN PO VBRITE VLAMP IOLAMP TA Recommended Operating Conditions Min. R.C. Max. 10 0.0 240 12 2.5 Units 14 4.0 2.2 650 7 60 500 5 0 V W V VRMS mA RMS °C ELECTRICAL CHARACTERISTICS Unless otherwise specified, these specifications apply over the recommended operating conditions and 25°C ambient temperature for the LXM1598. Parameter Symbol Test Conditions IL (MAX) IL (MIN) VLS fO VBRITE = 2.2 V DC, SLEEP = Logic High, VIN = 12V, V OUT = 400VRMS VBRITE = 0.0 V DC, SLEEP = Logic High, VIN = 12V, V OUT = 400VRMS IOUT set to 5mA RMS, VOUT = 400VRMS , 10.0 ≤ VIN ≤ 14VDC 0°C < TA < 60°C VBRITE = 2.2VDC, SLEEP = Logic High, VIN = 12V IBRITE VC VBRITE = 0V DC IO (LAMP) = 100% Min. LXM1598 Typ. Max. Units Output Pin Characteristics Full Bright Lamp Current Minimum Lamp Current IOUT Regulation vs. V IN Lamp Start Voltage Operating Frequency 6.5 4.75 1300 7.0 1.3 5.00 7.5 5.25 mA mA RMS mA VRMS KHz -1000 2.2 nADC VDC 5.5 0.8 VDC VDC µADC 2.50 500 2.60 VDC µADC 3 90 10 µADC % 50 Brightness Control Input Current Input Voltage for Max. Lamp Current 2.0 -200 2.1 SLEEP Input Input Logic 1 Input Logc 0 Input Current VIH VIL IIN 2.2 0 VSLEEP = 5VDC , VIN = 20V DC (Note 1) -150 Voltage Reference Output Voltage Output Current V REF IREF 0 < IREF < 500µA 2.40 250 Power Characteristics Sleep Current Electrical Efficiency (calculated values) IIN (MIN) η VIN = 5VDC , SLEEP = Logic 0 VIN = 12VDC, IO (LAMP) = 5mARMS Note 1: SLEEP pin is pulled up to V IN through a 100kΩ resistor and is clamped to not exceed 10VDC if VIN > 10V DC. 2 Copyright © 1998 Rev. 0.8a 10/00 PRODUCT DATABOOK 1996/1997 P AT E N T P E N D I N G LXM1598-01 12V CCFL I N V E R T E R M O D U L E S Not Recommended for New Designs FUNCTIONAL PIN DESCRIPTION Conn. CN1 Pin Description CN1-1 CN1-2 VIN Input voltage. (+10 to +14VDC) CN1-3 CN1-4 GND Power supply return. CN1-5 SLEEP 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 high and will enable inverter operation. CN1-6 BRITE Brightness control input. Apply 0.0 to 2.2 volts DC to control lamp brightness. Lamp current varies linearly with input voltage. 2.2V gives maximum brightness. CN1-7 AGND Brightness control signal return. For best results do not run power supply current return through this pin. CN1-8 VREF Reference Voltage Output. 2.5V @ 500µA max. For use with external dimming circuit. CN2-1 LAMP HI High voltage connection to high side of lamp. Connect to lamp terminal with shortest lead length. Do not connect to ground. CN2-2 LAMP LO High voltage connection to low side of lamp. Connect to lamp terminal with longer lead length. Do not connect to ground. CN2 MECHANICAL OUTLINE 3.93 (100) 1.02 (26.10) 1-1 Ø 0.116 (2.95) Location Hole 1.04 (26.40) 2-2 0.43 (11.00) 0.15 (3.85) 0.64 (16) 1-8 2-1 Connector CN-1 Ø 0.068 (1.75) Location Hole Connector CN-2 .326 Max. (8.3) Warning!! High Voltage Present .031 (0.79) All dimensions in inches (mm) Connectors: CN-1 = MOLEX 53261-0890 Recommended Mate: Pins: 50079-8100*, Housing: 51021-0800 CN-2 = JST SM02(8.0) B-BHS-TB Pins: 5BH-001T-P0.5, Housing: BHR-03VS-1 * Loose (-8000, Chain) Recommended #26 AWG wiring Note: All samples are equipped with connector mates and cable. Copyright © 1998 Rev. 0.8a 10/00 3 P AT E N T P E N D I N G PRODUCT DATABOOK 1996/1997 LXM1598-01 12V CCFL I N V E R T E R M O D U L E S Not Recommended for New Designs CONNECTION DIAGRAM 12VDC 13k 12VDC VREF 100K CMOS PWM LOGIC SIGNAL VIN CCFL TUBE LXM1598 VCC ON / OFF SLEEP LAMP HI CCFL TUBE LXM1598 LAMP HI BRITE AGND VIN BRITE ON/OFF CMOS LOGIC LAMP LO SLEEP GND LAMP LO GND Period PWM CMOS PULSE WIDTH 10µsec £ Period £ 100µsec 0 £ Pulse Width £ Period FIGURE 1 — Potentiometere Brightness Control FIGURE 2 — PWM Brightness Control 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. 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 4 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 = Light Output (in Nits) VIN (DC) * IIN (DC) = Nits Watt 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 = Eff 1 - Eff2 * 100 Eff2 The result of the above shows how much more efficient module #1 is than module #2. Copyright © 1998 Rev. 0.8a 10/00 PRODUCT DATABOOK 1996/1997 P AT E N T P E N D I N G LXM1598-01 12V CCFL I N V E R T E R M O D U L E S Not Recommended for New Designs EFFICIENCY MEASUREMENT SETUP DC Power Supply DC Amp Meter (continued) DC Volt Meter PIN = VDC * IDC Dimming Control Inverter Module Sleep Control = Logic "1" 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 © 1998 Rev. 0.8a 10/00 5