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Bet you can sell a lot of these if you ever considered it.
It's super easy to build a booster with that controller. Just follow the directions and use the standard application circuit on page 8 of the data sheet. The one negative about that controller is it's limited to 5.5V output, but you can probably squeeze 5.8V out of it if you milk it.I used that controller on the the first battery powered VV mod I built. Worked beautifully. Got about 85% efficiency average. It could put out 4A at 5.5V continuously with no heating issues in the least. Keep in mind, it is a booster so you'll need a good low DCR battery (either an IMR cell or a LiPo cell) especially if you want maximum output.I used a single 330uF tantalum polymer on both output and input instead of the dual electrolytics shown in the typical application. The tantalums are more expensive, but they're much more compact. You could probably just use a high value MLCC SMD cap on the input. I used the tantalum anyway, but it probably was not necessary. The output cap is the one that has to have high enough value and low enough ESR.Also pick a good rectifier diode with low forward voltage. Pick an inductor with low DCR and high saturation. Here's what I used; http://www.mouser.com/ProductDetail/Vishay-Dale/IHLM2525CZER1R0M01/?qs=bOnNDoERoR18uqA6UaJ%252bPgjMt2rhYMOEtdL3DIKYm04%3dhttp://www.mouser.com/ProductDetail/Diodes-Inc/PDS1040L-13/?qs=rNZh4F5RthQSjKiPhlxJLw%3d%3dGet the MAX1709 package with the thermal pad on the bottom of the chip. When you design/make the PCB for it, put a couple big vias underneth the thermal pad so you can solder it to the ground plane from underneath. The other option is to use reflow soldering with a bunch of small vias, but if you want to hand solder, that's how you can make the thermal connection.
No problem there, post what you like on this thread.You could try the SOIC package I supose, but it may go into thermal limiting at higher outputs. The TSSOP will not since it has the thermal pad. Those are really effective at dissipating heat when soldered to a ground plane. They work amazingly well.Since the TSSOP is a significantly smaller package, the pins are much smaller and you need a bunch in parallel to carry the current. So, to answer your question, the LX pins are all tied to together and the PG pins are all tied together. I just laid down one big pad for each set.The 2 Ohm resistor is there to act as a light filter for the feedback circuit. Current draw is very low there. You could use something as small as an 0402 package if you like.The feedback capacitors I used are the ones as shown in figure 1. R1 is only required for current limiting. Since we don't want to limit current, R1 can be removed. C3 governs the soft-start speed. .1uF (100nF) is a reasonable value for that one.Oh, one other note, figure 1 shows a set output voltage. Look at figure 4 to use a variable voltage. Replace R3 with the variable resistor. However, if using a digital pot, be careful not to power up the converter with the digital pot powered down. That puts Vout on the FB pin since R3 is absent. The FB pin is not tolerant to voltages greater than Vin. I burned a couple chips doing that.
Thanks, working on a smaller one right now, about a third shorter, found a 1300mAh cell for it that may work well. Really pulling my hair out on the PCB. It was already hard to stuff everything on the board size for the 2200. Got some bitchen 510 connectors coming I had custom made. They're made out of stanless steel with a brass post and delrin insulator. The nut is nickel plated brass so it's solderable. The fab sent me one to check before doing the production run on the rest of the order. The video shows the base and nut without the post and insulator in there;
30 watts is amazing for a boost mod. I don't believe I saw a boost mod put out that much wattage. Not even the Darwin which I think is spec'd at 15 watts max. Even stacking two DNA's are 24 watts max on paper.Cheers mate