description lation, lamp current regulation, and lamp dimming in a single power stage made up of two pairs 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 compo- nents can be used to obtain higher electri- cal efficiency than is possible with previous topologies. the full bridge LXM1597-01 is optimized to efficiently operate with up to 4 watt lamps at input voltages of 5 volts. this module will operate over the full 4.5v to 7v input voltage range. the modules are equipped with a dim- ming input that permits full range bright- ness control from an external potentiom- eter, 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. LXM1597-01 ccfl (cold cathode florescent lamp) inverter modules are specifically de- signed for driving lcd back light lamps in applications where dimmability, ultra-high efficiency, high light output, low noise emis- sions, reliable fail safe design, and small form factors are critical parameters. both mono- chrome and color displays are supported. the modules convert 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 pro- vides important new performance advances. remarkable improvements in efficiency and rf emissions result from its single stage resonant inverter featuring a patent pend- ing curr ent synchr onous, zero voltage switching (cs-zvs) topology. cs-zvs pro- duces 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 regu- product highlight b acklight i nverter l ight o utput e fficiency c omparison computer 1 computer 2 computer 3 stock linfinity 0 5 10 15 20 25 30 35 40 45 50 eff (nits / watts) 5v ccfl i nverter m odules not recommended for new designs t he i nfinite p ower of i nnovation LXM1597-01 lin d oc #: 1597 p atent p ending key features n 15 to 30% more light output n closed loop, fully regulating design n 4.5v to 7v input voltage range n versatile brightness control input n 3 microamp sleep current n output short circuit protection and automatic over-voltage limiting n 8mm max. height, narrow footprints n single sided pcb is self insulating applications nn nn n notebook and sub-notebook computers n personal digital assistants n portable instrumentation n automotive displays n desktop displays 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 standard modules fit into most lcd enclosures n single sided pcb saves expensive high voltage insulating tapes copyright ? 1998 rev. 0.6 a 10/00 1 11861 w estern a venue , g arden g rove , ca. 92841, 714-898-8121, f ax : 714-893-2570 l in f inity m icroelectronics i nc . important: for the most current data, consult linfinity's web site: http://www.linfinity.com. LXM1597-01 5v input module order info
5v ccfl i nverter m odules LXM1597-01 product databook 1996/1997 copyright ? 1998 rev. 0.6 a 1 0 /0 0 2 not recommended for new designs p atent p ending absolute maximum ratings (note 1) input supply voltage (v in ) .............................................................................................................................. ................................................. -0.3v to 7.0v output voltage, no load ........................................................................................................ ................................................ internally limited to 1900v rms output current ................................................................................................................. ........................................................ 8.0ma rms (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. 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, will not function optimally. input supply voltage v in 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. 4.5 5 7 v 2.5 4.0 w 0.8 2.5 v 240 500 650 v rms 57ma rms 060c electrical characteristics unless otherwise specified, these specifications apply over the recommended operating conditions and 25c ambient temperature for the lxm1597. full bright lamp current i l (max) v brite = 2.5 v dc , sleep = logic high minimum lamp current i l (min) v brite = 0.8 v dc , sleep = logic high lamp start voltage v ls 0c < t a < 60c operating frequency f o v brite = 2.5v dc , sleep = logic high, v in = 5v output pin characteristics parameter symbol test conditions units lxm1597 min. typ. max. 6.2 6.6 7.0 ma 2.6 ma rms 1300 v rms 50 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 2.2 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 = 5v dc , sleep = logic 0 electrical efficiency (calculated values) h lxm1597, v in = 5v dc , i o (lamp) = 5ma rms 310a dc 90 % input logic 1 v ih input logc 0 v il input current i in v sleep = 0 - 5v dc sleep input
5v ccfl i nverter m odules LXM1597-01 product databook 1996/1997 3 copyright ? 1998 rev. 0.6 a 1 0 / 00 not recommended for new designs p atent p ending functional pin description conn. pin description v in input voltage. (+4.5 to +7v 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 through a 33k w resistor to v in or directly to any voltage between 2.5 and 5.5v. brite 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. agnd brightness control signal return. for best results do not run 5v power supply current return 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 lo high voltage connection to low side of lamp. connect to lamp terminal with longer lead length. do not connect to ground. lamp hi high voltage connection to high side of lamp. connect to lamp terminal with shortest lead length. do not connect to ground. mechanical outline 4.79 (121.6) 3.88 (98.55) .40 (10.16) .160 (4.06) .400 (10.16) 0.125 (3.18) diameter hole, 2 places no other holes on board. .72 (18.29) 2-2 2-1 connector cn-2 connector cn-1 1-1 1-8 .031 (0.8) all dimensions in inches (mm) .315 max. (8) warning!! high voltage present connectors: recommended mate: cn-1 = molex 53261-0890 pins: 50079-8100*, housing: 51021-0800 * loose (-8000, chain) recommended #26 awg wiring cn-2 = jst sm02(8.0) b-bhs-tb pins: 5bh-001t-p0.5, housing: bhr-03vs-1 note: all samples are equipped with connector mates and cable.
5v ccfl i nverter m odules LXM1597-01 product databook 1996/1997 copyright ? 1998 rev. 0.6 a 1 0 / 00 4 not recommended for new designs p atent p ending connection diagram r 1 = 100k typical, 5k minimum r 2 = value optional to determine lowest brightness setting r 2 = 0.5 r 1 minimum lamp current (%) = x 100 v brite v ref 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. the end of the 30 minute period read the light output in cd/m 2 (1 cd/m 2 = 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 = = 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 num- bers as follows: percent more efficient = * 100 the result of the above shows how much more efficient mod- ule #1 is than module #2. light output (in nits) v in (dc) * i in (dc) nits watt eff 1 - eff 2 eff 2 equipment required 1) two dvm's with 0.1% or better accuracy. 2) a lab power supply. (0 - 20v, 0 - 2a) 3) the target notebook or lcd panel. 4) a tektronix j1803 luminance head. 5) a tektronix j17 luminance color photometer. 6) 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 mea- surements. the photometer luminance head (j1803) is posi- tioned directly in the center of the lcd screen. for best re- sults 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 LXM1597-01 v ref brite agnd from power management logic lamp hi v in sleep lamp lo gnd r 1 100k r 2 51k cmos or ttl gate cfl tube longest lead
5v ccfl i nverter m odules LXM1597-01 product databook 1996/1997 5 copyright ? 1998 rev. 0.6 a 1 0 / 00 not recommended for new designs p atent p ending efficiency measurement setup (continued) dc power supply dc amp meter dc volt meter inverter module sleep control = logic "1" dimming control ccfl j17 photometer p in = v dc * i dc j1803 luminance head 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.
|
