description key features n fully floating output n 35% more light output at 5 watts n grea ter efficiency than grounded output designs n 6.5v to 18v input voltage range n versatile brightness control input n 10 microamp sleep current n output short circuit protection and automatic over voltage limiting n 7.4mm max height, narrow footprint n minimize thermometer effects n minimize lamp to panel leakage current applications n n n n n 11.3" lcd panels and larger n n n n n notebook and sub-notebook computers n n n n n portable instrumentation n n n n n automotive displays n n n n n desktop displays n n n n n airline entertainment centers benefits n ultra-high efficiency, line voltage regulation and sleep mode extend computer battery life n cool operation permits close proximity to lcd panel without display distortion n smooth, full-range brightness control gives your product a high quality image n low emi / rfi design minimizes shielding requirements n narrow, low-profile module fits into most lcd enclosures 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 architec- ture 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 propri- etary linfinity ic that provides impor- tant new performance advances. remarkable improvements in efficiency and rf emissions result from this single stage resonant inverter, featuring a patented current synchro- nous, zero voltage switching (cs-zvs) topology. cs-zvs produces nearly pure sine wave currents in the lamp, product highlight f loating o utput a rchitecture f loating o utput d rive , ccfl i nverter m odules not recommended for new design t he i nfinite p ower of i nnova tion copyright ? 1997 rev. 0.2 3/03 for further information call (714) 898-8121 11861 w estern a venue , g arden g rove , ca. 92841 lin d oc #: 1653 1 p atent p ending module order info LXM1653-01 full-bridge drive 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 low- loss 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 shut- down mode. output open and short circuit protection are also featured on this module. ccfl dc v in cs-zvs inverter high voltage transformer LXM1653-01
f loating o utput d rive , ccfl i nverter m odules LXM1653-01 product databook 1996/1997 copyright ? 1997 rev. 0.2 3/03 2 p atent p ending absolute maximum ratings (note 1) input supply voltage (v in ).............................................................................................................................. ........................... 6.5v to 18v output voltage, no load ........................................................................................................ ...................... internally limited to 2000v rms output current ................................................................................................................. ............................. 7.5ma rms (internally limited) output power ................................................................................................................... ........................................................................ 6w 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 positiv e into, negative out of the specified terminal. 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 perfor mance 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. input supply voltage output power p o brightness control input voltage range v brite lamp operating voltage v lamp lamp current - full brightness i olamp operating ambient temperature range t a parameter symbol units recommended operating conditions min. r.c. max. 6.5 18 v 4.0 6.0 w 0.0 2.0 v 300 600 800 v rms 7.2 ma rms 060c electrical characteristics unless otherwise specified, these specifications apply over the recommended operating conditions and 25c ambient temperature f or the lxm1653. full bright lamp current i l (max) v brite = 2.0 v dc , v lamp = 750v rms , v in 3 10.8v dc v brite = 2.0 v dc , v lamp = 750v rms , v in 3 9.0v dc v brite = 2.0 v dc , v lamp = 350v rms , v in 3 6.5v dc v brite = 2.0 v dc , v lamp = 600v rms , v in 3 8.0v dc minimum lamp current i l (min) v brite = 0.0 v dc lamp start voltage v ls 0c < t a < 60c operating frequency f o v brite = 2.5v dc , sleep = logic high, v in = 12v output pin characteristics parameter symbol test conditions units lxm1653 min. typ. max. 6.8 7.2 7.7 ma 5.0 5.5 ma 6.8 7.2 ma 6.8 7.2 ma 2.5 ma rms 1800 v rms 55 60 65 khz brightness control input current i brite v brite = 0v dc input voltage for max. lamp current v c i o (lamp) = 100% input voltage for 50% lamp current v c i o (lamp) = 50% -200 -1000 na dc 2.4 2.5 2.6 v dc 1.25 v dc 2.5 5.5 v dc 0 0.8 v dc 50 100 a dc voltage reference output voltage v ref 0 < i ref < 500a output current i ref 2.40 2.50 2.60 v dc 500 a dc power characteristics sleep current i in (min) v in = 12v, sleep = logic 0 10 30 a dc input logic 1 v ih input logc 0 v il input current i in v sleep = 0 - 5v dc sleep input
f loating o utput d rive , ccfl i nverter m odules LXM1653-01 product databook 1996/1997 3 copyright ? 1997 rev. 0.2 3/03 p atent p ending functional pin description conn. pin description v in input voltage. (+6.5 to +18v dc ) gnd power supply return. 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 low and will disable inverter operation. if not used, connect sleep to v in . brite 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. agnd brightness control signal return. for best results do not run v in power supply return current through this pin. v ref reference voltage output. 2.5v @ 500a max. for use with external dimming circuit. cn1-1 cn1-2 cn1-3 cn1-4 cn1-5 cn1-6 cn1-7 cn1-8 cn1 cn2 cn2-1 cn2-2 lamp hi high-voltage connection to high side of lamp. connect to lamp terminal with shortest lead length. do not connect to ground. lamp lo 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. application diagram figure 1 maximum lamp current vs. input voltage for typical lamp voltages v in - (volts dc) 6 7891018 3.0 4.0 5.0 6.0 8.0 9.0 7.0 i lamp - (ma rms ) 350v rms v lamp = 60 0v rms v lamp = 65 0v rms v lamp = 70 0v rms v lamp = 76 0v rms
f loating o utput d rive , ccfl i nverter m odules LXM1653-01 product databook 1996/1997 copyright ? 1997 rev. 0.3 3/03 4 p atent p ending typical applications lxm1653 v ref brite agnd from power management logic lamp hi v in sleep lamp lo gnd r 1 cmos or ttl cfl tube insid e lcd panel 100k 3.3 or 5v sytem battery (nicd, nimh, etc.) ac/dc adapter r 2 , 25k figure 21 notebook system application figure 23 nonvolatile digital brightness control r 1 rh rw rl uc d dc +5v u1 from logic (optional) n.o. +5v s2 "decrease" n.o. +5v s1 "increase" lxm1653 v ref brite agnd 47k 47k s1 & s2 are momentary push buttons, normally open contacts. u1 = 100k digital pot. r 1 value optional for choosing dimming range. figure 22 potentiometer brightness control lxm1653 brite lamp hi v in sleep lamp lo gnd ccfl tube 12v dc 2.0v dc on / off 1k to 100k
f loating o utput d rive , ccfl i nverter m odules LXM1653-01 product databook 1996/1997 5 copyright ? 1997 rev. 0.2 3/03 p atent p ending typical applications (continued) figure 24 ? pwm brightness control lxm1653 brite lamp hi v in sleep lamp lo gnd ccfl tube 12v dc on / off pwm period pwm pulse width 10sec period 100sec 0 pulse width period
f loating o utput d rive , ccfl i nverter m odules LXM1653-01 product databook 1996/1997 copyright ? 1997 rev. 0.1 3/97 6 p reliminary d ata s heet p atent p ending physical dimensions cn-1 = molex p/n: 53261-0890 cn-2 = jst p/n: sm02-(8.0)b-bhs-1d lxm1653 5.35 (136) 5.256 (133.5) 0.512 (13.0) 2-1 cn-1 1-1 0.060 (1.52) all dimensions in inches (mm) 0.291 (7.40) max. warning!! high voltage present .089 (2.25) .089 (2.25) ? 0.089 (2.26) dia. mtg. hole 2 plcs 1 1 l1 t1 cn-2 .256 (6.5) conn entry conn entry
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