EV0022 (mp1522) precision 6 white led driver evaluation board EV0022 rev. 1.2 www.monolithicpower.com 1 9/1/2006 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2006 mps. all rights reserved. the future of analog ic technology description the EV0022 evaluation board uses the mp1522 to drive up to six (6) series white leds from a single cell lithium ion battery. the mp1522 uses a current limited, variable frequency architecture to regulate the led current, which is measured through an external current sense resistor. its 1.23v, 3% feedback threshold improves the led current regulation. the bias pin can measure the output voltage and turn off the converter to prevent damage in an open circuit condition. the mp1522 includes under-voltage lockout, current limiting and thermal overload protection preventing damage in the event of an output overload. the mp1522 is available in tiny 5-pin sot23 packages. electrical specification parameter symbol value units input voltage v cc 3.0 ? 5.5 v led current 20 ma features ? internal 0.5 ? power switch ? output voltage up to 25v ? up to 90% efficiency ? low 1a shutdown current ? input under-voltage protection ? thermal shutdown ? internal current limit applications ? handheld computers, pdas ? cell phones ? digital still and video cameras ? small lcd displays ?mps? and ?the future of analog ic technology? are registered trademarks of monolithic power systems, inc. EV0022 evaluation board dimensions (2.2?x x 1.5?y x 0.5?z) board number mps ic number EV0022 mp1522dt 80 70 60 50 40 30 20 10 0 efficiency (%) 0 5 10 15 20 25 led current (ma) efficiency vs led current 2 leds 3 leds 6 leds v in = 3.6v
EV0022 (mp1522) ? precision 6 white led driver evaluation board EV0022 rev. 1.2 www.monolithicpower.com 2 9/1/2006 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2006 mps. all rights reserved. evaluation board schematic u1 mp1522 sw fb bias gnd en 2 4 3 1 5 led1 led2 led3 led4 led5 led6 c3 10nf d1 b0530ws-7 j1 cn1 EV0022 bill of materials qty ref description package 1 u1 mp1522 sot23-5 1 l1 inductor, 6.8h d31fb 1 c1, c2 ceramic capacitor, 1f, 50v, x5r or x7r 0805 1 c3 ceramic capacitor, 10nf, 50v, x5r or x7r 0603 1 r1 resistor, 100k ? , 5% 0603 1 r2 resistor, 62 ? , 1% 0603 1 d1 schottky diode, 0.5a, 30v b0530w 6 led1 ? led6 not included with board
EV0022 (mp1522) ? precision 6 white led driver evaluation board EV0022 rev. 1.2 www.monolithicpower.com 3 9/1/2006 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2006 mps. all rights reserved. printed circuit board layout figure 1?top silk layer figure 2?top layer figure 3?bottom layer
EV0022 (mp1522) ? precision 6 white led driver evaluation board notice: the information in this document is subject to change without notice. users should warrant 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. EV0022 rev. 1.2 www.monolithicpower.com 4 9/1/2006 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2006 mps. all rights reserved. quick start guide 1. connect leds to led1 ? led6 terminals. 2. preset power supply to 3v v cc 5.5v. 3. turn power supply off. 4. connect power supply terminals to: a. positive (+): vcc b. negative (?): gnd 5. turn power supply on after making connections. 6. remove the jumper j1 to allow the mp1522 to automatically start when power is applied. place the shorting clip across j1 to disable the mp1522. a logic signal may be applied to en to enable/disable the mp1522, provided the shorting clip is not installed across j1. 7. to dim the leds remove the shorting clip from j1 and apply a pwm signal to the en pin. the duty cycle of the pwm signal determines the led current.
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