ev1528dq-00a 9 lamp, 20ma preciscion wled driver evaluation board ev1528dq-00a rev. 1.0 www.monolithicpower.com 1 10/11/2005 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2005 mps. all rights reserved. the future of analog ic technology tm tm general description the ev1528dq-00a evaluation board is designed for driving up to nine (9) series wleds from a single cell lithium ion battery. the board is set up to obtain 20ma led current. the current can be adjusted by varying the resistor r1. the mp1528 uses current limited, variable frequency architecture to regulate the led current while maintaining high efficiency. the bias pin measures the output voltage and turns off the converter if an over voltage condition is present to prevent damage due to an open circuit condition. the led current is measured with an external current sense resistor. the low 0.4v full-scale regulation threshold and 0.4 ? power switch minimize power loss to improve efficiency. either a dc voltage or a pwm signal at the brt input can control the led brightness. electrical specifications parameter symbol value units input voltage v in 2.7 ? 5.5 v # of wleds 7 ? 9 led current i led 20 ma features ? 2.7v to 5.5v input voltage range ? drives up to 9 series white leds ? analog and digital pwm brightness control through brt ? surface-mount components ? fully assembled and tested applications ? handheld computers ? pdas ? pda phones ? digital and video cameras ? small lcd displays ?mps? and ?the future of analog ic technology? are trademarks of monolithic power systems, inc. ev1528dq-00a evaluation board (l x w x h) 2.0? x 1.5? x 0.5? (5.0cm x 3.8cm x 1.4cm) board number mps ic number ev1528dq-00a MP1528DQ 90 80 70 60 50 40 efficiency (%) 0 5 10 15 20 25 led current (ma) mp1528_ec01 efficiency vs load current 3v 5v 3.6v 4.2v v in =
ev1528dq-00a ? 9 lamp, 20ma precision wled driver ev board ev1528dq-00a rev. 1.0 www.monolithicpower.com 2 10/11/2005 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2005 mps. all rights reserved. tm evaluation board schematic led1 ev1528_s01 led9 mp1528 en brt bias 2 1 3 5 6 4 gnd fb sw d1 b160b-13-f vin gnd brt gnd en u1 c3 10nf ev1528dq-00a bill of materials qty ref value description package manufacturer p/n distributor p/n 1 c1 4.7f ceramic capacitor, 10v, x5r 1206 tdk: c3216x5r1a475k digikey: 445-1386-1-nd 1 c2 1f ceramic capacitor, 50v, x7r 1206 tdk: c3216x7r1h105k digikey: 445-1423-1-nd 1 c3 10nf ceramic capacitor, 50v, x7r 0805 tdk: c2012x7r1h103k digikey: 445-1348-1-nd 1 d1 diode schottky, 60v, 1a sma diodes inc.: b160b-13-f digikey: b160b-fdict-nd 1 l1 6.2h inductor, 1.45a, d62lcb smd toko: a918cy-6r2m 9 led1 to led9 not stuffed 1 r1 20 ? resistor, 1% 0805 panasonic: erj-6geyj200v digikey: p20act-nd 1 r2 100k ? resistor, 5% 0805 panasonic: erj-6geyj104v digikey: p100kact-nd 1 u1 white led driver qfn6 mps: MP1528DQ
ev1528dq-00a ? 9 lamp, 20ma precision wled driver ev board notice: the information in this document is subject to change wi thout notice. please contact mps for current specifications. users should warrant and guarantee that third party intellectual property rights ar e not infringed upon when integrating mps products into any application. mps will not assume any legal responsibility for any said applications. ev1528dq-00a rev. 1.0 www.monolithicpower.com 3 10/11/2005 mps proprietary information. unaut horized photocopy and duplication prohibited. ? 2005 mps. all rights reserved. tm printed circuit board layout figure 1?top silk layer figure 2?top layer figure 3?bottom layer quick start guide 1. solder led1 - led9 to the board. 2. attach the positive and negative terminals of the power supply (2.7v - 5.5v) to the vin and gnd pins, respectively. 3. drive en high to enable the mp1528. 4. apply a dc voltage of 0.3v to 1.2v on brt for analog dimming. maximum brightness (20ma typical) occurs with 1.2v applied. for pwm dimming mode, apply a pwm rectangular wave with a minimum voltage less than 0.18v and a maximum greater than 1.2v. when a voltage less than 0.18v is applied to this pin, the output switch is turned off. the frequency of the pwm signal must be between 100hz to 400hz.
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