e u p 2589 ds 2 589 ver1.1 may 2011 1 12 s t ring white led driver with boost controller description the eup2589 is a high power and high efficiency boost controller with 12-channel current sinker which is ideal for large lcd backlighting applications. eup2589 uses current mode, fixed frequency architecture which can clamp the inductor peak current each cycle. the switching frequency is programmable by an external frequency setting resistor. it drives an external mosfet to boost up the output voltage from a 4.5v to 28v input supply. the eup2589 regulates the current in each led string to the programmed value set by an external current setting resistor. the eup2589 current matching can achieve 1.5% and regulation accuracy can reach 2%. a 3 a shutdown current and 1.0v (iled@60ma) feedback voltage and maximum 65v output allows for up to 18 high-power leds in series will greatly improve efficiency and reduce power dissipation. the device supports pulse width modulation (pwm) brightness dimming and dc voltage dimming. during digital pwm dimming, the wled current is turned on/off at the duty cycle and frequency determined by the pwm signal on the pwmi pin. in dc voltage dimming, leds current turn on/off frequency programmed by the capacitor from bosc to gnd. the eup2589 integrated multiple protect functions, such as led open, led short, output over voltage, over thermal, input over current, and under voltage lockout (uvlo), these protection will prevent the lcd backlight from damage. features 3 a shutdown current 12 strings in parallel and up to 18 leds per string external pwm or dc voltage dimming control output voltage up to 65v wide input voltage range 4.5v to 28v better than 1.5% led current regulation accuracy between strings boost switching frequency can be programmed by external resistor multiple fault protections -current limit protection -output short circuit detection -over-temperature protection -output over-voltage protection led current turn off in shutdown mode integrated uvlo/ over thermal protection minimal 0.5 s led on-time regulation thermal enhanced 28pin tssop28 and sop-28 packages rohs compliant and 100% lead (pb)-free halogen-free applications lcd monitor led backlighting lcd-tv led backlighting typical application circuit figure 1. typical application circuits v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 2 pin configurations package type pin configurations package type pin configurations tssop-28 sop-28 pin description pin tssop-28 sop-28 description 1 nc nc not connect. 2 vin vin supply voltage input. 3 vcc vcc 5v linear regulator output to power internal circuitry. bypass vcc to gnd with a ceramic capacitor of 1f or greater. if 4.5v eup2589 ds2589 ver1.1 may 2011 3 pin description pin tssop-28 sop-28 description 27 fault fault fault disconnection switch gate output. when the system starts up normally, this pin smoothly turns on the external pmos. when the eup2589 is disabled, the external pmos is turned off to disconnect the input and output. 28 nc nc not connect thermal pad gnd - ch1~ch12 current mirror ground. ordering information order number package type mark ing operating temperature range eup2589xir1 tssop-28 (ep) xxxxx eup2589 -40 c to +85c EUP2589YIR1 sop-28 xxxxx eup2589 -40 c to +85c eup2589 lead free code 1: lead free, halogen free 0: lead packing r: tape & reel operating temperature range i: industry standard package type x: tssop (ep) y: sop block diagram figu re 2. block diagram n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 4 absolute maximum ratings (1) ch (n), ics to gnd ---- ---------------------------------------------------- ----------------- -0.3v to 65v vin, fault to g nd ------------------------------------------------- ----------------------- -0.3v to 30v pgnd to gnd ---- ---------------------------------------------------- ----------------------- -0.3v to +0.3v com p, ovp, drv, pwmi, en, i set , fset, bosc, vcc to gnd ----------------- -0.3v to +6v continuous power dissipation (t a = +70c) 28-p in tssop [derate 29.4mw/c (jedec high-k 2s2p) above +70c] ------------------ 2353mw 28-p in sop [derate 16.67mw/c (jedec high-k 2s2p) above +70c] ------------------- 1333mw operating temperature range ---- ---------------------------------------------------- ---- -40c to +85c maximum junction temperature ---- ---------------------------------------------------- --------- +150c storage temperature range ---- ---------------------------------------------------- ------ -60c to +150c lead temperature (soldering, 10s) --- - ---------------------------------------------------- --------- +300c operating conditions (2) operating temperature range ------------------------------------------------------------- -40c to +85c supply voltage , vin------------------------------------------------------------------------------ 4.5v to 28v note (1): stress beyond those listed under absolute maximum ratings may damage the device. note (2): the device is not guaranteed to function outside the recommended operating conditions. elec trical characteristics (circuit of figure 1, vin=12v, gnd=pgnd=0v, r iset =20k , v pwmi = 5v, t a = 40c to +85c, unless otherwise note d. typical values are at t a = +25c.) eup2589 symbol parameter conditions min. typ. max. unit vin vin supply voltage 4.5 28 v i_vin vin supply current pwmi=5v 2.5 5 ma i_off vin shutdown current pwmi=0v, en=0,vin=12v 6 a vcc vcc output voltage ven=5v, 6v eup2589 ds2589 ver1.1 may 2011 5 electrical characteristics (continued) (circuit of figure 1, vin=12v, gnd=pgnd=0v, r iset =20k , v pwmi = 5v, t a = 40c to +85c, unless otherwise note d. typical values are at t a = +25c.) eup2589 symbol parameter conditions min. typ. max. unit dimming controls tpwmimin minimum pwm pulse in external pwm dimming mode 0.5 s vpwmh pwmi input high level 1.5 vin v vpwml pwmi input low level 0 0.4 v ipwmi pwmi pull down current v pwmi =5v -1 +1 a fault detections vovp over-voltage threshold on ovp rising edge 1.2 1.25 1.3 v vhys-ovp ovp hysteresis falling edge 80 mv vchx_ov chx over voltage threshold v in >5.5v 5.1 5.5 5.9 v ifault fault pull down current 40 55 70 a vfault fault clamp voltage vin=12v, vfault=vin-v fault 6 v tsd thermal shutdown threshold 150 oc tsd_hys thermal shutdown hysteresis 30 oc n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 6 typical operating characteristics efficiency vs. input voltage steady state v in startup v en startup dc burst dimming external pwm dimming v pwm1 =0.4v, c bosc =2.0nf f pwm =200hz d pwm =50% 0.70 0.75 0.80 0.85 0.90 0.95 6 11 16 21 26 input voltage(v) efficiency 2 s/div v sw 20v/div v out (ac) 1v/div v led1 1v/div i led1 20ma/div 2ms/div v sw 20v/div v out 20v/div v in 5v/div i led 200ma/div 2ms/div v sw 20v/div v out 20v/div v en 5v/div i led 200ma/div 400 s/div v sw 20v/div v out 20v/div v bosc 500mv/div i led 200ma/div 2ms/div v sw 20v/div v out 20v/div v pwm11 5v/div i led 200ma/div n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 7 typical operating characteristics (continued) open led protection short led protection open all led strings at working short v out to gnd at working 100 s/div v sw 20v/div v out 20v/div v fault 5v/div i led 200ma/div 10ms/div v sw 20v/div v out 50v/div v fault 5v/div i led 200ma/div n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 8 detailed descriptions the eup2589 is a high-efficiency driver for arrays of white leds. it contains a fixed-frequency, current mode, pwm step-up controller, 5v linear regulator, dimming control circuit, and 12 regulated current sources (see figure 2). when enabled, the step-up controller boosts the output voltage to provide sufficient headroom for the current sources to regulate their respective string currents. the eup2589 features programmable switching frequency, which allows trade-offs between external component size and operating efficiency. the control architecture automatically skips pulses at light loads to improve efficiency and prevents overcharging the output capacitor. the eup2589 supports both analog and digital control of the led current through a pwm logic input signal or dc level on pwmi. the eup2589 has multiple features to protect the controller from fault conditions. separate feedback loops limit the output voltage if one or more leds fail open or short. the controller features cycle-by-cycle current limit to provide consistent operation and soft-start capability. a thermal-shutdown circuit provides another level of protection. this part includes a 5v linear regulator that provides the internal bias and gate drive for the step-up controller. when an external 5v is available, the internal ldo can be overdriven to decrease power dissipation. otherwise, connect the vin pin to an input greater than 5.5v. an internal crude ldo keeps alive to provide power supply for internal logic and controller even en is low, which only dissipate 3 a quiescent current. 5v supply vcc and uvlo the eup2589 has built in 5v linear regulator vcc supply f or internal control voltage. the eup2589 includes the power on reset (por) and under-voltage lockout (uvlo) features. por resets the fault latchs. por occurs when vcc rises above 2.8v (typ). the controller is disabled until vcc exceeds the uvlo threshold of 4.05v (typ). hysteresis on uvlo is approximately 150mv. the vcc should be bypassed to gnd with a 0.47 f or greater ceramic capacitor. system startup when the eup2589 is enabled, the chip checks the topology c onnection first. the fault pin drives the external fault disconnection pmos to turn on slowly. and after 8ms delay, the chip monitors the ovp pin to see if the schottky diode is not connected or the boost output is short to gnd. if the ovp voltage is lower than 70mv, the chip will be disabled and the external pmos is turned off together. it is recommended on the start up sequence that the enable signal comes after input voltage and pwm dimming signal established. step- u p converter the converter operation frequency is programmable (from 150khz to 1mhz) with a external set resistor on fset pin, which is helpful for optimizing the external components sizes and improving the efficiency. an oscillator resistor on fset pin sets the internal oscillator frequency for the step-up converter according to the equation: for r fset =112k , the switching frequency is set to 500khz. th e eup2589s fixed-frequency, current-mode, step-up controller automatically chooses the lowest active chx voltage to regulate the output voltage. when iled=60ma, a 1.0v is setting as the minimum chx feedback reference. the error signal is compared to the external switch current plus slope compensation to determine the switch on-time. as the load changes, the error amplifier sources or sinks current to the comp output to deliver the required peak-inductor current. the slope-compensation signal is added to the current-sense signal to improve stability at high duty cycles. at light-load or vout near to vin operation, the converter runs into the pulse-skipping mode, the fet is turned on for a minimum on-time of approximately 100ns, and then the converter discharges the power to the output in the remain period. the external mosfet will keep off until the output voltage needs to be boosted again. dimming control the eup2589 provides two pwm dimming methods: extern a l pwm signal or dc input pwm dimming mode. both methods results in pwm chopping of the current in the leds for all 12 channels to provide led control. when bias the bosc pin to a dc level, applying a pwm signal to the pwmi pin to achieve the pwm dimming. a dc analog signal can be directly applied to the pwmi pin to modulate the led current. and the dc signal is then converted to a dpwm dimming signal at the setting oscillation frequency. the brightness of the led array is proportional to the duty cycle of the dpwm signal. the dpwm signal frequency is set by the cap at the bosc pin. 1. direct pwm dimming an external pwm dimming signal is employed to achieve pwm dimming control. connect a 100k resistor from bosc pi n to gnd and apply the 100hz to 2khz pwm dimming signal to pwmi pin. the minimum recommended amplitude of the pwm signal is 1.5v (see figure 3). fset sw r/5 7 000 f = n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 9 figure 3. direct pwm dimming 2. dc input pwm dimming to apply dc input pwm dimming, apply an analog signal (range from 0 v to 1.2v) to the pwmi pin to modulate the led current directly. if the pwmi is applied with a zero dc voltage, the pwm duty cycle will be 0%. if the dbrt pin is applied with a dc voltage>1.2v, the output will be 100% (see figure 4). the capacitor on bosc pin set the frequency of internal triangle waveform according to the equation: figure 4. dc input pwm dimming open string protection the open string protection is achieved through the over vol t age protection. if one or more strings are open, the respective chx pins are pulled to ground and the ic keeps charging the output voltage until it reach ovp threshold. then the part will mark-off the open strings whose chx pin voltage is less than 210mv. once the mark off operation completes, the remaining led strings will force the output voltage back into tight regulation. the string with the highest voltage drop is the ruling string during output regulation. the eup2589 always tries to light at least one string and if all strings in use are open, the eup2589 shuts down the step-up converter. the part will maintain mark-off information until the part shuts down. setting the over voltage protection t he open string protection is achieved through the over vol t age protection (ovp). in some cases, an led string failure results in the feedback voltage always zero. the part then keeps boosting the output voltage higher and higher. if the output voltage reaches the programmed ovp threshold, the protection function will be triggered. to make sure the chip functions properly, the ovp setting resistor divider must be set with a proper value. the recommended ovp point is about 1.2 times higher than the output voltage for normal operation. short string protection the eup2589 monitors the chx pin voltage to judge if the short string occurs. if one or more strings are shorted, the respective chx pins will be pulled up to the boost output and tolerate high voltage stress. if the chx pin voltage is higher than 5.5v, the short string condition is detected on the respective string. when the short string fault (chx over-voltage fault) continues for greater than 2ms, the string is marked off and disabled. once a string is marked off, its current regulation is forced to disconnect from the output voltage loop regulation. the marked-off led strings will be shut off totally until the part restarts. if all strings in used are short, the eup2589 will shut down the step-up converter. f ault protection the eup2589 has multiple features to protect the device f r om fault conditions. separate feedback loops limit the output voltage under any circumstance, ensuring safe operation. once an open string is detected, the string is disabled while other strings operate normally. the eup2589 also features short led detection. table 1 lists all the eup2589 fault protections control. bosc bosc c/f5.3f m = ? ? ? ? ? ? ? ? + = 2 21 ovp r rr 2 3.1 v n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 10 table 1. eup2589 fault protection faults fault output (hv) ic operation mode boost dc-dc wled current chx short to gnd pull lo, enable pch normal only 12chx all off, controller will shutdown. otherwise, keep normal mark off the shorted chx, others keep normal chx over voltage pull lo, enable pch normal only 12chx all off, controller will shutdown. otherwise, keep normal mark off the led open chx, others keep normal ovp shorted to gnd or boost schottky diode malfunction (v ovp <0.07v) pull hi, disable pch normal off off dc-dc boost output exceeds ovp threshold (v ovp =1.23v) pull lo, enable pch normal when v ovp is greater than 1.23v, the boos controller will be turned off until v ovp drops to 1.18 v. on thermal fault (tj>+150oc) pull lo, enable pch normal off first, then return to soft- start after tj falls below 120oc off first, then return to soft- start after tj falls below 120oc en lo pull hi, disable pch shutdown, iq<6 a off off n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 11 packaging information tssop-28 m i l limeters inches symbols min. max. min. max. a - 1.20 - 0.047 a1 0.00 0.15 0.000 0.006 b 0.19 0.30 0.007 0.012 e1 4.40 0.173 d 9.60 9.80 0.378 0.386 d1 3.05 3.55 0.120 0.139 e 6.20 6.60 0.244 0.260 e2 2.62 3.12 0.103 0.122 e 0.65 0.026 l 0.45 0.75 0.018 0.030 n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2589 ds2589 ver1.1 may 2011 12 sop-28 millimeters inc h es symbols min. nom. max. min. nom. max. a 2.36 2.49 2.64 0.093 0.098 0.104 a1 0.10 0.30 0.004 0.012 a2 2.34 0.092 b 0.33 0.41 0.51 0.013 0.016 0.020 c 0.23 0.25 0.30 0.009 0.010 0.012 d 17.70 17.91 18.11 0.697 0.705 0.713 e 10.01 10.31 10.64 0.394 0.406 0.419 e1 7.39 7.49 7.59 0.291 0.295 0.299 e 1.27 bsc 0.050 bsc l 0.38 0.81 1.27 0.015 0.032 0.050 0 8 0 8 n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
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