LXM1653-01

P ATENT P ENDING LIN D O C # : 1653 LXM1653-01 F L OAT I N G O U T P U T D RIV E , CCFL I NVER TER M O D U L E S T HE I NFINITE P OWER OF I N N O VAT I O N P RELIMINARY D ATA S HEET DESCRIPTION The LXM1653 floating output drive CCFL (Cold Cathode Fluorescent Lamp) Inverter Module is specifically designed to drive large LCD displays (11.3" and larger), which are used in notebook computers. This new inverter was specifically designed to reduce the leakage currents from the lamp to the reflector or the metal frame of the panels. The floating output architecture of this inverter also permits a much wider dimming range when compared to non-floating designs, and allows an additional 10% efficiency improvement. The module converts unregulated DC voltage from the system battery or AC adapter directly to high-frequency, high-voltage 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 this single stage resonant inverter, featuring a patented C urrent 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 two tasks including line voltage regulation and lamp dimming through lamp current regulation. These two functions are performed in a single power stage made up of a pair of low-loss MOSFETs. The MOSFETs drive a low current 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 lowloss components can be used to obtain higher electrical efficiency than is possible with previous topologies. The full-bridge LXM1653 provides peak efficiency when operated at input voltages from 6.5 volts to 18 volts. In addition, this module is equipped with a dimming input that permits full range brightness control from an external potentiometer or PWM signal, and a sleep input that reduces module power to a few microwatts in shutdown mode. Output open and short circuit protection are also featured on this module. K E Y F E AT U R E S s FULLY FLOATING OUTPUT s 35% MORE LIGHT OUTPUT AT 5 WATTS s GREATER EFFICIENCY THAN GROUNDED OUTPUT DESIGNS s 6.5V TO 18V INPUT VOLTAGE RANGE s VERSATILE BRIGHTNESS CONTROL INPUT s 10 MICROAMP SLEEP CURRENT s OUTPUT SHORT CIRCUIT PROTECTION AND AUTOMATIC OVER VOLTAGE LIMITING s 7.4mm MAX HEIGHT, NARROW FOOTPRINT s MINIMIZE THERMOMETER EFFECTS s MINIMIZE LAMP TO PANEL LEAKAGE CURRENT A P P L I C AT I O N S s 11.3" LCD PANELS AND LARGER s NOTEBOOK AND SUB-NOTEBOOK COMPUTERS 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 MODULE FITS INTO MOST LCD ENCLOSURES PRODUCT HIGHLIGHT FLOATING OUTPUT A RCHITECTURE High Voltage Transformer CS-ZVS Inverter DC VIN MODULE ORDER CCFL INFO FULL-BRIDGE DRIVE LXM1653-01 F O R F U R T H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1 Copyright © 1997 Rev. 0.1 3/97 11861 WESTERN A VENUE , G ARDEN G ROVE , CA. 92841 1 P AT E N T P E N D I N G PRODUCT DATABOOK 1996/1997 LXM1653-01 F L O AT I N G O U T P U T D RIV E , CCFL I NVERTER M O D U L E S P RELIMINARY D ATA S HEET (Note 1) A B S O L U T E M A X I M U M R AT I N G S Input Supply Voltage (VIN)......................................................................................................................................................... 6.5V to 18V Output Voltage, no load .............................................................................................................................. Internally Limited to 2000VRMS Output Current .............................................................................................................................................. 7.5mARMS (Internally Limited) Output Power ........................................................................................................................................................................................... 6W 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 Input Supply Voltage Output Power Brightness Control Input Voltage Range Lamp Operating Voltage Lamp Current - Full Brightness Operating Ambient Temperature Range Symbol Recommended Operating Conditions Min. R.C. Max. 6.5 4.0 0.0 300 0 600 7.2 18 6.0 2.0 800 60 Units V W V VRMS mA RMS °C PO VBRITE VLAMP IOLAMP TA ELECTRICAL CHARACTERISTICS Unless otherwise specified, these specifications apply over the recommended operating conditions and 25°C ambient temperature for the LXM1653. Parameter Output Pin Characteristics Full Bright Lamp Current Symbol Test Conditions VBRITE = 2.0 VDC , VLAMP = 750VRMS, VIN ≥ 10.8VDC VBRITE = 2.0 VDC , VLAMP = 750VRMS, VIN ≥ 9.0VDC VBRITE = 2.0 VDC , VLAMP = 350VRMS, VIN ≥ 6.5VDC VBRITE = 2.0 VDC , VLAMP = 600VRMS, VIN ≥ 8.0VDC VBRITE = 0.0 V DC 0°C < TA < 60°C VBRITE = 2.5VDC, SLEEP = Logic High, VIN = 12V VBRITE = 0V DC IO (LAMP) = 100% IO (LAMP) = 50% Min. 6.8 5.0 6.8 6.8 1800 55 LXM1653 Typ. Max. 7.2 5.5 7.2 7.2 2.5 60 -200 2.5 1.25 7.7 Units IL (MAX) Minimum Lamp Current Lamp Start Voltage Operating Frequency IL (MIN) VLS fO IBRITE VC VC VIH VIL IIN V REF IREF IIN (MIN) 65 -1000 2.6 mA mA mA mA mA RMS VRMS KHz nADC VDC VDC VDC VDC µADC VDC µADC µADC 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 2.5 0 VSLEEP = 0 - 5VDC 0 < IREF < 500µA 2.40 500 50 2.50 5.5 0.8 100 2.60 Voltage Reference Output Voltage Output Current Power Characteristics Sleep Current VIN = 12V, SLEEP = Logic 0 10 30 2 Copyright © 1997 Rev. 0.1 3/97 PRODUCT DATABOOK 1996/1997 P AT E N T P E N D I N G LXM1653-01 F L O AT I N G O U T P U T D RIV E , CCFL I NVER TER M O D U L E S P RELIMINARY D ATA S HEET FUNCTIONAL PIN DESCRIPTION Conn. CN1 CN1-1 CN1-2 CN1-3 CN1-4 CN1-5 Pin Description VIN GND SLEEP Input voltage. (+6.5 to +18VDC ) 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 to VIN. Brightness control input. Apply 0.0 to 2.0 volts DC to control lamp brightness. Lamp current varies linearly with input voltage. Open circuit or 2.0V gives maximum brightness. This input may also be driven with a PWM logic signal. See Application Notes Section. Brightness control signal return. For best results do not run VIN power supply return current through this pin. Reference Voltage Output. 2.5V @ 500µA max. For use with external dimming circuit. CN1-6 BRITE CN1-7 CN1-8 AGND VREF CN2 CN2-1 CN2-2 LAMP HI LAMP LO High-voltage connection to high side of lamp. Connect to lamp terminal with shortest lead length. Do not connect to ground. High-voltage connection to low side of lamp. Connect to lamp terminal with longer lead length. This lead may be safely connected to ground, but may not result in specified performance depending on system wiring and lamp characteristics. A P P L I C AT I O N D I A G R A M 9.0 8.0 MS MS MS ILAMP - (mARMS) =6 00V R =6 50V R =7 00V R AM P VL AM P VL 5.0 4.0 3.0 6 7 8 9 10 18 VIN - (Volts DC) FIGURE 1 — MAXIMUM LAMP CURRENT vs. INPUT VOLTAGE FOR TYPICAL LAMP VOLTAGES Copyright © 1997 Rev. 0.1 3/97 VL V LA MP AM P 6.0 350 VR =7 60 V 7.0 MS RM S 3 P AT E N T P E N D I N G PRODUCT DATABOOK 1996/1997 LXM1653-01 F L O AT I N G O U T P U T D RIV E , CCFL I NVERTER M O D U L E S P RELIMINARY D ATA S HEET T Y P I C A L A P P L I C AT I O N S AC/DC Adapter R2, 25k R1 100k 3.3 or 5V From Power Management Logic VREF BRITE VIN LAMP HI CFL TUBE Inside LCD Panel Sytem Battery (NiCd, NiMH, etc.) LXM1653 SLEEP AGND LAMP LO GND CMOS or TTL FIGURE 21 — NOTEBOOK SYSTEM APPLICATION 12VDC 2.0VDC 1K TO 100K VIN BRITE LAMP HI CCFL TUBE LAMP LO GND LXM1653 ON / OFF SLEEP FIGURE 22 — POTENTIOMETER BRIGHTNESS CONTROL +5V S1 "Increase" From Logic (optional) N.O. +5V U1 47k N.O. UC D RH RW RL R1 VREF BRITE AGND • S1 & S2 are momentary push buttons, normally open contacts. • U1 = 100k digital pot. • R1 value optional for choosing dimming range. S2 "Decrease" 47k +5V DC LXM1653 FIGURE 23 — NONVOLATILE DIGITAL BRIGHTNESS CONTROL 4 Copyright © 1997 Rev. 0.1 3/97 PRODUCT DATABOOK 1996/1997 P AT E N T P E N D I N G LXM1653-01 F L O AT I N G O U T P U T D RIV E , CCFL I NVER TER M O D U L E S P RELIMINARY D ATA S HEET T Y P I C A L A P P L I C AT I O N S 12VDC VIN PWM BRITE (continued) LAMP HI CCFL TUBE LAMP LO LXM1653 ON / OFF SLEEP GND PWM Period PULSE WIDTH 10µsec £ Period £ 100µsec 0 £ Pulse Width £ Period FIGURE 24 — PWM BRIGHTNESS CONTROL Copyright © 1997 Rev. 0.1 3/97 5 P AT E N T P E N D I N G PRODUCT DATABOOK 1996/1997 LXM1653-01 F L O AT I N G O U T P U T D RIV E , CCFL I NVERTER M O D U L E S P RELIMINARY D ATA S HEET PHYSICAL DIMENSIONS LXM1653 5.35 (136) Conn Entry 5.256 (133.5) 1-1 .089 (2.25) CN-1 1 1 CN-2 L1 T1 0.512 (13.0) .256 (6.5) .089 (2.25) Ø 0.089 (2.26) Dia. Mtg. Hole 2 Plcs 2-1 Conn Entry 0.291 (7.40) Max. Warning!! High Voltage Present 0.060 (1.52) All dimensions in inches (mm) CN-1 = MOLEX P/N: 53261-0890 CN-2 = JST P/N: SM02-(8.0)B-BHS-1D 6 Copyright © 1997 Rev. 0.1 3/97