general description the max8631x evaluation kit (ev kit) is a fully assem-bled and tested circuit for evaluating the max8631x white led 1x/1.5x/2x charge pump with two ldos. the max8631x ev kit drives 4 white leds for backlighting and uses 4 flash led drivers to drive a flash led mod- ule at a high current. the two 200ma ldos are also available for evaluation. in addition to the led driver circuit and ldos, the ev kit includes one pulse-genera- tor circuit and two momentary pushbutton switches that are used for testing the single-wire, serial-pulse-dim- ming and flash features of the max8631x. the max8631x ev kit can also evaluate the max8631y. to evaluate the max8631y, order a free sample along with this ev kit. features ? max8631x powers up to 4 main leds and 4 flashleds ? ev kit powers 4 main leds and a flash ledmodule ? 94% maximum/85% average efficiency(p led /p batt ) over li+ battery discharge ? 0.2% typical led current matching ? adaptive 1x/1.5x/2x mode switchover ? single-wire, serial-pulse interface (3% to 100%brightness) ? thermal t a derating function ? two internal low-noise 200ma ldos ? 2.7v to 5.5v supply voltage range ? soft-start, overvoltage, and thermal-shutdownprotection ? 4mm x 4mm 28-pin thin qfn ic package ? fully assembled and tested evaluates: max8631x/max8631y max8631x evaluation kit _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ maxim integrated products 1 ordering information designation qty description c1, c5 2 10? ?0%, 6.3v x5r ceramiccapacitors (0805) tdk c2012x5r0j106m or murata grm219r60j106m c3, c4, c6, c7 4 1? ?0%, 6.3v x5r ceramiccapacitors (0402) tdk c1005x5r0j105m or murata grm155r60j105k c8 1 0.01? ?0%, 25v x7r ceramiccapacitor (0402) tdk c1005x7r1e103k or murata grm155r71e103k c9 1 1000pf ?0%, 50v x7r ceramiccapacitor (0402) tdk c1005x7r1h102k or murata grm155r71h102k c10 1 2.2? ?0%, 6.3v x5r ceramiccapacitor (0603) tdk c1608x5r0j225k or murata grm185r60j225k d1?4 4 white ledsnichia nscw215t designation qty description d5 1 lednichia nbcw011t d6 1 sod-523 diode, cmosh-3central semiconductor ju1, ju2, ju3, ju5 4 3-pin headers ju4 1 2-pin headers ju6?u9 0 not installed, pc board shorts r1 1 6.81k ?% resistor (0402) r2 1 5.11k ?% resistor (0402) r3 1 22.1k ?% resistor (0402) r4 1 100k ?% resistor (0402) r5 1 2.2k ?% resistor (0402) s1, s2 2 momentary pushbutton switchespanasonic evq-php03t u1 1 white led charge pump(28 tqfn-ep*) maxim max8631xeti u2 1 6-channel pmic (40 tqfn)maxim max6816eus-t 5 shunt, two positions 1 pcb: max8631x evaluation kit component list 19-3834; rev 1; 6/08 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part type MAX8631XEVKIT ev kit * ep = exposed pad. downloaded from: http:///
evaluates: max8631x/max8631y quick start recommended equipment before beginning, the following equipment is needed:? a 2.7v to 5.5v power supply or a lithium batterycapable of delivering 1.5a ? two digital multimeters (dmms) ? two 200ma loads ? ammeter (optional) procedure the max8631x ev kit is fully assembled and tested.follow the steps below to verify board operation: 1) preset the power supply to between 2.7v and 5.5v. 2) turn off the power supply. caution: do not turn on the power supply until all connections are com-pleted. 3) verify that the shunt on ju3 is connected to off (pins 2-3). verify that the shunt on ju5 is connectedto on (pins 1-2). verify that there is a shunt on ju4. verify that there is no shunt on ju1 and ju2. 4) connect the positive power-supply terminal to the pad on the ev kit labeled in. 5) connect the power-supply ground terminal to the pad on the ev kit labeled gnd. 6) connect a dmm across the ldo1 pad on the ev kit and the gnd pad on the ev kit. 7) connect a dmm across the ldo2 pad on the ev kit and the gnd pad on the ev kit. 8) turn on the power supply and verify that the main leds are lit. 9) push s2 for only a short duration to verify that the flash led module lights. holding s2 down for longdurations may damage the flash led module. see the detailed description section for testing the dim- ming and shutdown features. 10) remove the shunt from the off position (pins 2-3) of ju3 and place on the on position (pins 1-2) ofju3. 11) verify the voltage at ldo1 is near 2.6v. 12) connect a 200ma load between ldo1 and gnd. 13) verify the voltage at ldo1 is near 2.6v. 14) verify the voltage at ldo2 is near 1.8v. 15) connect a 200ma load between ldo2 and gnd. 16) verify the voltage at ldo2 is near 1.8v. detailed description led dimming of the main display to test the dimming feature, press the button labeleddim main. each button depression dims the main leds by 3.125%. due to the logarithmic response of the human eye, it takes many depressions of the button to visually notice dimming. the 31st pulse reduces the current to 3.125%. the 32nd pulse sets the led current back to 100%. refer to the max8631x data sheet for more information on the dimming feature. single-wire pulse dimming for main or flash using external pulse generators to use an external pulse generator in place of the pulsegenerator included with the ev kit or to reduce the num- ber of control traces, the max8631x supports serial- pulse dimming. connect the output of the external pulse generator to enm1 or enm2 to enable single-wire pulse dimming of the main leds. use enf for single- wire pulse dimming of the flash led module. the ground of the external pulse generator should be con- nected to the ev kit pad labeled gnd. ensure that there is a shunt on ju5 connected to on (pins 1-2). when enm1 and enm2 (or enf) go high simultaneous- ly, the main (or flash) leds are enabled at full bright- ness. each subsequent low-going pulse (500ns to 250? pulse width) reduces the led current by 3.125% (1/32), so after one pulse the led current is 96.9% (or 31/32). the 31st pulse reduces the current to 3.125%. max8631x evaluation kit 2 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ supplier phone website central semiconductor corp. 631-435-1110 www.centralsemi.com murata electronics north america, inc. 770-436-1300 www.murata-northamerica.com nichia corp. 248-352-6575 www.nichia.com panasonic corp. 800-344-2112 www.panasonic.com tdk corp. 847-803-6100 www.component.tdk.com component suppliers note: indicate that you are using the max8631x or max8631y when contacting these component suppliers. downloaded from: http:///
the 32nd pulse sets the led current back to 100%.figure 1 shows a timing diagram for single-wire pulse dimming. because soft-start is longer than the initial t hi , apply dimming pulses quickly upon startup (after initialt hi ) to avoid led current transitioning through full brightness. note there is a 2.2k pullup resistor from enm2 to in on the ev kit and a 100k pulldown resistor connected to enf. flash led to test the flash feature, press the button labeledflash. this button should only be held for short dura- tions to prevent overheating of the flash led module. jumper ju4 is provided to allow for lower current test- ing of the flash led module, typically called movie mode in cell phone applications. the shunt on jumper ju4 can be removed for testing the flash led module at 75ma total (18.7ma per f_). to test without the push- button switch, use enf to control the flash led opera- tion; refer to the max8631x/max8631y ic data sheet for more information. note that there is a 100k pull- down resistor connected to enf. adjusting the main 100% brightness level the full-brightness led current for the main display isadjustable by changing the resistor r1. calculate the value of r1 with the following equation, where i m_ is the sink current through each m_ current regulator with thedimming set to 100%: adjusting the flash 100% brightness level the full-brightness led current for the flash isadjustable by changing resistors r2 and r3. calculate the value of r t with the following equation, where i f_flash is the sink current through each f_ current regulator with the dimming set to 100%:where r t is the parallel combination of r2 and r3. r3 is the low-current-set resistor, which must be calculatedfirst using the equation below. i f_movie is the sink cur- rent through each f_ current regulator in movie mode:once r3 is determined, then r2 can be calculated using the following equation: r2 = rr rr t t 3 3 r 0.6v 9 3 f_movie = 60 i r 0.6v 9 t f_flash = 60 i r 0.6v 2 m_ 1 30 = i evaluates: max8631x/max8631y max8631x evaluation kit _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 enm1 and enm2or enf i m_ or i f_ shdn 32/32 31/32 30/32 29/32 28/32 27/32 5/32 4/32 3/32 2/32 1/32 32/32 31/32 shdn 1 32 31 30 29 28 27 5 4 3 2 t lo 500ns to 250 s t hi 500ns t shdn (2.5ms) 0 t soft-start initial t hi 200 s figure 1. enm_ and enf timing diagram downloaded from: http:///
evaluates: max8631x/max8631y shutdown control one jumper is included on the ev kit for shutting downthe main leds. to turn off the main leds, place the shunt on the off side of jumper ju5 (pins 2-3). note that with ju5 shunted off, power is disconnected from the pulse-generator circuit. the max8631x is in low- power shutdown mode when both ju5 and ju3 are shunted off since flash is nominally off (see the low- dropout (ldo) regulator section). changing the number of leds the ev kit comes with four leds for the main displayand a flash led module. to use fewer leds, locate the small pad (labeled tp_) next to the led to be removed and connect it to the pad on the ev kit labeled tp9. connecting external leds to connect external leds to the max8631x ev kit, cutthe trace shorting ju7. connect the anodes of all the external leds to the small pad labeled tp9. connect the cathodes to the small pads next to d1?8 (tp1?p4 for the main leds, tp5?p8 for the flash leds). connect any unused pads (tp1?p8) to the pad labeled tp9. also, cut ju8 and ju9 as needed to sup- port individual flash leds. low-dropout (ldo) regulator ldo shutdown one jumper is included on the ev kit for shutting downboth ldos. to turn off the ldos, place the shunt on the off side (pins 2-3) of jumper ju3. to turn on the ldos, place the shunt on the on side (pins 1-2) of jumper ju3. ldo output voltage selection (p1 and p2) as shown in table 1, the ldo output voltages, ldo1and ldo2, are pin programmable by the logic states of p1 (jumper ju1) and p2 (jumper ju2). p1 and p2 are tri- level inputs: in (pins 1-2), open, and gnd (pins 2-3). the input voltage, v in , must be greater than the select- ed ldo1 and ldo2 output voltages to prevent dropout.the logic states of p1 and p2 can be programmed only when enldo is low. once the ldo_ voltages are pro- grammed, their values do not change by changing p1 or p2 when enldo is high. when evaluating the max8631y, refer to the max8631x/max8631y ic data sheet for the ldo out- put-voltage selection. evaluating the max8631y for evaluating the max8631y, carefully remove themax8631x (u1) and install the max8631y. all other components can remain the same. max8631x evaluation kit 4 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ table 1. p1 and p2, ldo output voltageselection for max8631x p1 p2 ldo1 (v) ldo2 (v) gnd gnd 2.5 1.8 gnd open 2.8 1.8 gnd in 3.0 1.8 in gnd 2.8 1.5 in open 3.0 1.5 in in 3.3 1.8 open gnd 2.6 1.5 open open 2.6 1.8 open in 3.3 1.5 downloaded from: http:///
evaluates: max8631x/max8631y max8631x evaluation kit _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5 in u2 2 41 c102.2 f r5 2.2k c9 1000pf enm2 enm1 gnd in in s1 2322 2627 12 3 2420 19 21 8 2516 15 14 13 12 11 10 9 7 1828 out gnd v cc 17 45 c1pc1n pin in gnd pgnd enm1 enm2 enf setm c2p tp9 tp1tp2 d1 ju7 ju8ju9 ju4 ju1 ju2 ju3 ju6 ldo1 enldo enf ldo2 12 3 in in in d2d3 d4 d5 tp3tp4 tp5 tp6 tp7 tp8 r322.1k r25.11k r16.81k r4 100k c41 f c510 f c2nout m1m2 m3 m4 f1f2 f3 f4 setf enldop1 d6 p2ldo1 ldo2 refbp 6 in s2 max6816 u1 max8631x c8 0.01 f c6 1 f c7 1 f c3 1 f c1 10 f 12 3 1 2 3 3 ju5 in 1 2 3 figure 2. max8631x ev kit schematic downloaded from: http:///
evaluates: max8631x/max8631y max8631x evaluation kit 6 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ figure 3. max8631x ev kit component placement guide?omponent side figure 4. max8631x ev kit pcb layout?omponent side downloaded from: http:///
evaluates: max8631x max8631x evaluation kit _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 7 figure 5. max8631x ev kit pcb layout?older side downloaded from: http:///
evaluates: max8631x/max8631y max8631x evaluation kit maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2008 maxim integrated products is a registered trademark of maxim integrated products. inc. revision history revision number revision date description pages changed 0 9/05 initial release 1 5/08 removed pwm dimming control feature. 3 downloaded from: http:///
|
