ev-118 aat3152 eval: high efficiency 1x/1.5x/2x charge pump for white led applications introduction the aat3152 eval board demonstrates the functionality of the aat3152 and its application as a white led backlight driver. the aat3152 is a low-noise, constant frequency charge pump dc/dc converter with tri-mode load switch (1x), fractional (1.5x), and doubling (2x) conversion to maximize efficiency and operate over a wide input voltage range. the aat3152 is programmable with the s 2 cwire? (simple serial control?) serial interface and is capable of driving up to four independent led channels. main/sub control is available with eight constant current level settings from 20ma down to 50a. this document describes the evaluation board and its accompanying user interface. in addition, a brief getting started section is included to help the user begin operating the evaluation board. a schematic of the complete circuit is shown in figure 1, and the actual board layout is given in figures 2 and 3. for additional informa- tion, please consult the aat3152 product datasheet. schematic figure 1: evaluation board schematic. vdd 1 gp5 2 gp4 3 gp3 4 gp2 5 gp1 6 gp0 7 vss 8 pic12f675 u2 c3 1 f c1 1 f c2 1 f c4 1 f r6 100k ? r1 1k ? r4 330 ? r5 330 ? c5 10 f r2 1k ? r3 1k ? r7 220 ? j1 1 2 3 4 5 0 down sw1 1 2 3 4 5 0 up sw2 red led7 1 2 3 4 5 0 cycle sw3 dc+ dc- d2 d1 d4 d3 gnd dc+ gnd gnd pot 10k vr4 grn led0 gnd d4 1 en/set 2 c1+ 3 c1- 4 vout 5 c2+ 6 c2- 7 vin 8 gnd 9 d1 10 d2 11 d3 12 aat3152 u1 gnd gnd j2 gnd jp6 dc+ jp5 jpx ev-118.2005.06.1.0 1
getting started in most cases, the board ships mounted onto a battery pack. the battery pack holds three aaa size, conven- tional alkaline batteries. a jumper is inline with the battery supply for connecting/disconnecting power. there is an additional jumper labeled on srl off. it provides access to en/set. for operation, ensure that it is in the on srl position. to apply power to the board, connect the supply by jumpering on, mcu. the red led7 should illuminate, indicating that power has been connected. the user interface is provided by three buttons: cycle, up, and down. the modes of operation are detailed in table 1. each button handles a particular function. the cycle button toggles on/off auto-cycling. the up button increments to the next number of en/set edges. when the up button is held down, the mcu will auto- increment through all of the settings after a short delay. pressing the down button decrements the number of en/set edges. when the down button is held, the mcu will auto-decrement through all of the settings. user interface functionality table 1: user interface functionality. button(s) pushed 1 description cycle 2 toggle on/off auto-cycling. auto-increments en/set edges and cycles through the available brightness level settings. up increment the number of en/set edges. toggles through the available brightness level settings for the backlighting section. if held down, auto-cycle through the settings. down decrement the number of en/set edges. toggles through the available brightness level settings for the backlighting section. if held down, auto-cycle through the settings. cycle + up + down reset. enable line is pulled low. ev-118 aat3152 eval: high efficiency 1x/1.5x/2x charge pump for white led applications 2 ev-118.2005.06.1.0 1. the '+' sign indicates that these buttons are all pressed and released together. 2. the auto-cycling speed is adjusted with the 10k pot, vr4. turn clockwise to speed up and counter-clockwise to slow down.
printed circuit board figure 2: top layer (not to scale). figure 3: bottom layer (not to scale). ev-118 aat3152 eval: high efficiency 1x/1.5x/2x charge pump for white led applications ev-118.2005.06.1.0 3
aat3152 eval component listing table 2: component listing. component part number description manufacturer u1 aat3152 high efficiency 1x/1.5x/2x charge pump analogictech for white led; tdfn33-12 package u2 pic12f675 8-bit cmos, flash-based c; 8-pin microchip pdip package d1-d4 lw m673 mini-topled white led; smt package osram r1-r3 chip resistor 1k ? , 5%, 1/4w; 1206 vishay c1-c4 ecj-1vb1a105k 1f, 10v, x5r, 10%; 0603 panasonic-ecg j1, j2 prpn401paen connecting header, 2mm zip sullins electronics led0 cmd15-21ugc/tr8 green led; 1206 chicago miniature lamp led7 cmd15-21src/tr8 red led; 1206 chicago miniature lamp c5 grm31cr70j106ka01l 10f, 6.3v, x7r, 10%; 1206 murata r4, r5 chip resistor 330 ? , 5%, 1/4w; 1206 vishay r6 chip resistor 100k ? , 5%, 1/4w; 1206 vishay r7 chip resistor 220 ? , 5%, 1/4w; 1206 vishay jpx chip resistor 0 ? , 5%; 0603 vishay jp5, jp6 chip resistor 0 ? , 5%; 0805 vishay vr4 evn-5esx50b14 10k pot; 3mm squared smd panasonic-ecg sw1-sw3 pts645tl50 switch tact, spst, 5mm itt industries ev-118 aat3152 eval: high efficiency 1x/1.5x/2x charge pump for white led applications 4 ev-118.2005.06.1.0 advanced analogic technologies, inc. 830 e. arques avenue, sunnyvale, ca 94085 phone (408) 737-4600 fax (408) 737-4611 analogictech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an analogictech pr oduct. no circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. analogictech reserves the right to make changes to their products or specifications or to discontinue any product or service wi thout notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. all products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of l iability. analogictech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accorda nce with analogictech?s standard warranty. testing and other quality control techniques are utilized to the extent analogictech deems necessary to support this warranty. specific tes ting of all parameters of each device is not necessarily performed.
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