mp1519 1x, 1.5x, 2x high efficiency charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 1 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. the future of analog ic technology tm tm description the mp1519 is a fully automatic driver for powering four white leds, with up to 4v forward voltage, from a single li-ion or three nimh cells. the driver performs all of the sensing and control to run the leds at an optimum charge pump ratio for efficiency without an expensive inductor. the driver allows pwm operation to support brightness control. the tiny 3mm x 3mm qfn16 package and small external capacitors allow for the most compact white led solution available. evaluation board reference board number dimensions ev0042 2.4?x x 1.9?y x 0.4?z features ? 2% led current matching ? high efficiency (>93%) ? current source outputs ? no ballast resistors required ? 1x, 1.5x and 2x automatic modes ? constant frequency operation ? automatic led detection ? high and low frequency pwm capability ? 2.5v to 5.5v operation ? less than 1 a leakage during shutdown ? detects changes in battery level ? no external schottky diode required ? soft-start and soft switching operation applications ? cell phones ? pda or hand held computers ? white led application at 3.6v supply ?mps? and ?the future of analog ic technology? are trademarks of monolithic power systems, inc. typical application mp1519 c1a c1b c2a c2b led1 led2 led3 led4 batt en radj gnd ledc gnd enable batt led4 led3 led2 led1 4 7 6 9 14 15 16 5, 13 12 11 3, 10 8 1 100 90 80 70 60 50 40 30 20 10 0 efficiency (%) 2.5 3.0 3.5 4.0 4.5 supply voltage (v) efficiency vs supply voltage v led = 3.35v @ 20ma i led =20ma i led =10ma i led =5ma
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 2 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm package reference part number* package temperature mp1519dq qfn16 (3mm x 3mm) ?40 c to +85 c * for tape & reel, add suffix ?z (eg. mp1519dq?z) for rohs compliant packaging, add suffix ?lf (eg. mp1519dq?lf?z) absolute maxi mum ratings (1) v batt to gnd .............................................. 6.5v power dissipation (qfn) ........................... 1.0w logic inputs to gnd ................... ?0.3v to +6.5v storage temperature ..............?65 c to +150 c junction temperature...............................150 c recommended operating conditions (2) input voltage vbatt ...................... 2.5v to 5.5v operating temperature .............?40 c to +85 c thermal resistance (3) ja jc 3x3 qfn16 ............................. 60 ...... 14... c/w notes: 1) exceeding these ratings may damage the device. 2) the device is not guaranteed to function outside of its operating conditions. 3) measured on approximately 1? square of 1 oz copper. electrical characteristics v batt = 5v, t a = +25 c, unless otherwise noted. parameter symbol condition min typ max units input supply voltage v batt 2.5 5.5 v v batt at 1x to 1.5x mode switch v batt 1x-1.5x i led = 20ma, v batt decreasing, v led = 3.35v @ 20ma 3.6 v v batt at 1.5x to 2x mode switch v batt 1.5x-2x i led = 20ma, v batt decreasing, v led = 3.35v @ 20ma 2.8 v v batt at 2x to 1.5x mode switch v batt 2x-1.5x v batt increasing, v led = 3.35v @ 20ma 3.1 v v batt at 1.5x to 1x mode switch v batt 1.5x-1x v batt increasing, v led = 3.35v @ 20ma 3.8 v supply current i batt 4 leds at 20ma, 2x mode, v batt = 2.5v 164 180 ma supply current shutdown i batt shdn v en = 0v 0.1 1 a current matching (4) i led match i led = 20ma 1.5 5.0 % enable voltage, high v en (high) 2.0 2.2 v enable voltage, low v en (low) 0.8 1.0 v enable pin leakage i en v en = 5v 0.1 1 a charge pump frequency f cp v batt = 3.3v 1.0 1.3 1.6 mhz time to standby mode (5) t off enable switched low 30 s enable pin pwm frequency limit f hpwm 50 khz led current i led r set = 1.54k ? 18 20 22 ma notes: 4) matching is defined as the difference of the maximum to minimum current divided by the sum of the maximum and minimum curren ts. 5) standby mode switches to shutdown when the output voltage on ledc drifts back to gnd. top view exposed pad connect to pin 8 pin 1 id led4 nc gnd c1a en radj gnd c2b 1 2 3 4 13 14 15 16 8 7 6 5 ledc c1b c2a batt batt led1 led2 led3 12 11 10 9
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 3 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm typical performanc e characteristics v batt 20mv/div. v ledc 20mv/div. 400ns/div. voltage ripple in 1.5x mode 4 x 10ma leds v en 5v/div. i batt 100ma/div. startup in 1.5x mode 4 x 10ma leds analog dimming circuit of figure 3, v batt = 3.6v v en 5v/div. i batt 100ma/div. startup in 1x mode 4 x 10ma leds 16 14 12 10 8 6 4 2 0 led current (ma) 0123 dc voltage (v) 12 11 10 9 8 7 6 led current (ma) 2.5 3.0 3.5 4.0 4.5 supply voltage (v) led current matching led1 led2 led3 led4
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 4 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm pin functions pin # name description 1 led4 #4 led driver. connect the #4 led between led4 and ledc, with the anode at led4, and the cathode at ledc. if the #4 led is not used, leave led4 unconnected. 2 nc no connect. 3, 10 gnd ground. 4 c1a charge pump capacitor #1 positive node. connect the positive side of the #1 charge pump capacitor to c1a. typical applications require c1 to be 1 f. 5, 13 batt battery power input. connect the 2.5v to 5. 5v input source between batt and gnd. bypass batt to gnd with a 1 f or greater capacitor. 6 c2a charge pump capacitor #2 positive node. connect the positive side of the #2 charge pump capacitor to c2a. typical applications require c2 to be 1 f. 7 c1b charge pump capacitor #1 negative node. co nnect the negative side of the #1 charge pump capacitor to c1b. 8 ledc led common for the cathodes. connect the cath odes of the leds to ledc and to a 4.7 f bypass capacitor. do not connect to any other ground, supply or pin. note: exposed pad on backside is connected to this pin. do not ground. 9 c2b charge pump capacitor #2 negative node. co nnect the negative side of the #2 charge pump capacitor to c2b. 11 radj led current adjust input. connect a resistor between radj and gnd to set the led current. all of the leds regulate at the same current. see setting the led current. 12 en enable input. drive en high to turn on the mp151 9, drive en low to shutdown the mp1519. to use burst-mode brightness control, drive en with a pwm signal. see burst mode dimming. 14 led1 #1 led driver. connect the #1 led between led1 and ledc, with the anode at led1, and the cathode at ledc. if the #1 led is not used, leave led1 unconnected. 15 led2 #2 led driver. connect the #2 led between led2 and ledc, with the anode at led2, and the cathode at ledc. if the #2 led is not used, leave led2 unconnected. 16 led3 #3 led driver. connect the #3 led between led3 and ledc, with the anode at led3, and the cathode at ledc. if the #3 led is not used, leave led3 unconnected.
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 5 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm operation the mp1519 is a charge pump that drives 4 leds from a 2.5v to 5.5v input voltage. it automatically switches between 1x, 1.5x and 2x charge pump modes to optimize efficiency while maintaining led current regulation. four drivers independently regulate the current through the leds, therefore matching leds are not required. the mp1519 employs soft switching and soft-start to prevent overloading the battery source at turn-on and charge pump mode switching. while operating, the mp1519 continually monitors the led current and battery voltage and automatically switches between charge pump modes to retain led current regulation through all leds as the battery voltage fluctuates. current generator controller led enable iset shutdown radj gnd en batt 11 3, 10 12 5, 13 charge pump 1.25v bandgap reference battery sensor pump mode soft start led4 led3 led2 led1 fault current source fault current source fault current source fault current source c2b batt enable c2a c1b c1a ledc led4 led3 led2 led1 9 6 7 4 8 1 16 15 14 figure 1?functional block diagram
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 6 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm application information component selection startup when power is applied to the batt, driving en high will enable the mp1519. the mp1519 begins by checking for open leds and determining the optimum charge pump mode. the lowest charge pump mode that allows the programmed led current in all leds is set. this will occur during initial turn-on or during analog mode and burst mode dimming. shutdown driving en low for more than 30 s will disable the mp1519. for safety the mp1519 runs a small supervisory circuit in standby to protect the charge pump output ledc. the circuit shuts down when the charge pump output returns to zero volts (this can take a few seconds). the mp1519 is in true shutdown mode when ledc is zero and the 30 s time interval has passed. the supply current should be less than 1 a. setting the led current the led regulation current is set through the resistor r1 (refer to the typical application circuit on page 1). the voltage across r1 is fixed at 1.25v, and the current through that resistor sets the current through the leds. figure 2 shows led current (i led ) vs. r1 with v batt = 3.6v. 25 20 15 10 5 0 led current (ma) 0 5 10 15 20 figure 2?i led vs. r1 choose r1 for the desired led current according to the equation: led i 31.25 r1 = where r1 is in k ? , and i led is in ma. suitable values for r1 are greater than 1.2k ? . soft-start during startup and mode switching, an internal soft-start prevents excessive input current, preventing excessive loading of the battery or input power source. burst mode dimming to dim the part using burst mode, drive en with a pwm signal. each time en is driven high, the mp1519 goes through the initial startup routine and checks for open leds, and the charge pump step-up mode is reset. when en goes low, the led current immediately goes to zero. after en is held low for 30 s or longer, and ledc falls below gnd, the mp1519 operating current drops below 1 a to improve battery life. maintain the frequency of the pwm signal between 50hz and 50khz. going above 50khz the accuracy of the pwm signal will be degraded due to the startup time, and below 50hz, the led flicker will be evident to the eye. ideally, the led current increases proportionally with the duty cycle of the pwm signal and is independent of the dimming frequency. analog mode dimming analog dimming can be accomplished with the circuit in figure 3. the circuit provides 1ma to 15ma dimming with v dc = 0 to 3v. the minimum led current the mp1519 can regulate is approximately 1ma. ledc do not drive or force ledc as it may be shorted to ground or may be pumped down by the controller in the mp1519 at any time. excessive capacitance on the ledc node can cause the internal controller to time out before the charge pump can be ready. missing the timeouts will cause excessive pumping and a loss of efficiency. the mp1519 requires c1 and c2 be of the same value and type.
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver mp1519 rev. 1.9 www.monolithicpower.com 7 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm typical application circuits mp1519 c1a c1b c2a c2b led1 led2 led3 led4 batt en radj gnd ledc gnd enable batt led4 led3 led2 led1 v dc 0v to 3v 4 7 6 9 14 15 16 5, 13 12 11 3, 10 8 1 figure 3?analog dimming circuit
mp1519 ? 1x, 1.5x, 2x charge pump 4 white led driver notice: the information in this document is subject to change wi thout notice. users should warra nt and guarantee that third party intellectual property rights are not infringed upon w hen integrating mps products into any application. mps will not assume any legal responsibility for any said applications. mp1519 rev. 1.9 www.monolithicpower.com 8 10/8/2007 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2007 mps. all rights reserved. tm package information qfn16 (3mm x 3mm) side view top view 1 16 13 12 9 8 5 4 bottom view 2.90 3.10 1.50 1.80 2.90 3.10 1.50 1.80 0.50 bsc 0.18 0.30 0.80 1.00 0.00 0.05 0.20 ref pin 1 id marking 1.70 0.50 0.25 recommended land pattern 2.90 note: 1) all dimensions are in millimeters. 2) exposed paddle size does not include mold flash. 3) lead coplanarity shall be 0.10 millimeter max. 4) drawing conforms to jedec mo-220, variation veed-4. 5) drawing is not to scale. pin 1 id see detail a pin 1 id option a 0.30x45 o typ. pin 1 id option b r0.20 typ. detail a pin 1 id index area 0.70 0.30 0.50
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