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How would you like free boost driver designs?! :drool:
So this is a boost driver based on the lm3410. Single li-ion or 2x/3x alkaline/nimh ONLY. It is meant to drive diodes with a Vf greater than the input voltage, like 445 and 405 diodes. It has been tested at a little under 1.2A on a 445nm diode and worked great, it may go a bit higher but I wouldn't expect anything over 1.3A. These drivers can also be paralleled to get higher currents like 1.8A. Rhd currently has a build using two of these drivers in parallel and is going to make a thread about it, I'll pop in the link when he does.
Here is the parts list:
Q1:
P-channel mosfet - $0.79: Digi-Key - SI3473CDV-T1-GE3CT-ND (Manufacturer - SI3473CDV-T1-GE3)
R1, R2:
Set Resistors (0805) - VARIES
C1, C2, C3:
3x 10uF Caps - $0.54: Digi-Key - 490-3347-1-ND (Manufacturer - GRM21BF51C106ZE15L)
D1:
Shottky - $0.47: Digi-Key - 568-4105-1-ND (Manufacturer - PMEG1020EH,115)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Changelog
R6 R9: Original posted design. Has reverse polarity protection, 0805 caps, No OVP.
R6 R9 Round v6: Originally posted design (0805 caps, no OVP) on a 16.5mm board to go right into most flashlight pills, with battery contacts on the bottom.
R6 R10: Replaced 0805 caps with 1206 caps (not as tall).
C1, C2, C3:
3x 10uf caps - $0.60 Digi-Key - 490-3383-1-ND (Manufacturer - GRM31MF51C106ZA12L)
Tseele those caps would work fine assuming they fit. But they are a huge ripoff
Is there any advantage to the 1206 package vs the 0805 package for the regular (not round) benboost?
Ok, this has me confused...
Newark Caps comparison
Looking at that, I can have my cake and eat it too with the TDK versions.
CAPACITOR CERAMIC, 10UF, 16V, X7R, 1206 at @ $0.17
Is there something wrong with that?
I get the 125C operating temp, but at a low price. Would this be a good compo of price and improved high temp performance?
Thanks for being patient with me AnthoT!
Yup those will work fine :beer: tseele if you like I can revise the original BenBoost to fit 1206 for ya it would work the same and be the same size, that way you won't have a problem fitting them, Ill do it when I get home
Typically, it will be much harder to solder a 1206 capacitor to the pads of an 0805 capacitor. However, it should fit, as long as there isn't anything in relatively close proximity.
Hold on,
I'm confused here. Let me make sure I am communicating my side well.
I bought a hundred of Moh's Benboost PCB's.
They are R6 (fork again) R9
He lists the 0805 in the parts list, but I couldn't tell from the first post if the 1206 would fit also and just be shorter. Maybe I should stick with the 0805 package to be sure?
I hate to rain on everyone's parade -
But the 1206 vs 805 debate is totally misguided.
If you're choosing between one and the other, you should be asking yourself which form factor will fit the board better. That's your consideration. Period.
You'll run into a lot more trouble if you foolishly try to strive for some meaningless additional "temperature rating" at the expense of using the part shape that your PCB was designed for.
It's silly. This is a silly silly silly debate. You're not talking about a current set resistor that actually generates some heat. You're talking about caps. Those caps are never going to get near 120 degrees, unless you're doing something majorly wrong.
Sorry for being critical
You're not talking about a current set resistor that actually generates some heat.
Furthermore, even if it isn't exceeding 85C, a part rated for 125C is going to last a lot longer at 70-80C than a part rated for 85C.