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[UPDATE] V4 BlitzBuck, Available Soon!

ARG

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Re: BlitzBuck V3, Available Soon!

Wolfman29 said:
Hmm. That sounds... odd. It may be the result of overheating, which may indicate that the IC itself is faulty, because everything looks like a clean joint. Is it possible that you can see if the two are related? I.e. does something in particular heat up and then the current rises, or what?
Click to expand...

The inductor and IC heat up fast, the IC becomes to hot to touch in about 20 seconds, and the inductor is very warm.

The current starts to rise imediatly after turning it on.
 





Wolfman29

Wolfman29

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Re: BlitzBuck V3, Available Soon!

The heating of the inductor is normal. What isn't normal, though, is the IC heating up. Just speculating here, but this board may not have reflowed properly and the thermal ground at the bottom of the IC may not have made very good contact with the pad below. Since I can't inspect that, I would never notice that happening. If that's the case, simply sticking it in a toaster oven for about 5 minutes should fix it (only do it though if you are comfortable reflowing). Otherwise, I can't say I have any idea what would be happening. The inductor is on properly (the numbers should be parallel to the pins on the IC), everything looks soldered properly... this is a very bizarre anomaly. But, these being produced in large quantities, it does happen and I hope you understand that.

I'm sure Clif will take care of you if you so desire ^_^
 
ARG

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Re: BlitzBuck V3, Available Soon!

Wolfman29 said:
The heating of the inductor is normal. What isn't normal, though, is the IC heating up. Just speculating here, but this board may not have reflowed properly and the thermal ground at the bottom of the IC may not have made very good contact with the pad below. Since I can't inspect that, I would never notice that happening. If that's the case, simply sticking it in a toaster oven for about 5 minutes should fix it (only do it though if you are comfortable reflowing). Otherwise, I can't say I have any idea what would be happening. The inductor is on properly (the numbers should be parallel to the pins on the IC), everything looks soldered properly... this is a very bizarre anomaly. But, these being produced in large quantities, it does happen and I hope you understand that.

I'm sure Clif will take care of you if you so desire ^_^
Click to expand...

There's still the possibility something is wrong with my DMM/Testload/PowerSupply. I'll hook up my other driver tomorrow and if it acts the same way then it's my setup.
 
ARG

ARG

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Re: BlitzBuck V3, Available Soon!

Okay, so I hooked up my other blitz buck and I added some small Al blocks on the IC and Inductor of this one. I hooked it up and it started doing the same thing.

I've asked my friend who is an electronics guru and he says my testload resistor is too small and too hot. I've only used my testload for a few <1A drivers before, so I guess the 2A current is too much for it. I'm going to go to the electronics store and get a 20W power resistor later.

Sorry for bugging you with this, I feel really silly now :rolleyes:
 
clif

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Re: BlitzBuck V3, Available Soon!

You could always try it at 1.2amps just to see what it does - that should pull less than one amp at 8.4vdc input. Assuming your 1 ohm resistor is still good to go.
 
Fiddy

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Re: BlitzBuck V3, Available Soon!

heatsinked my blitzbuck's today :)

buckdriver1.jpg

bickdriver2.jpg


Also Wolfman, one of my drivers is missing a resistor for the sense?

what value and size must they be?
 
Last edited:
Wolfman29

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Re: BlitzBuck V3, Available Soon!

Nice heatsinks! You sure it's missing a sense resistor? o.o That seems odd. But, if it really is missing a sense resistor, you can just replace it with any sense resistor you want to get any current range lower!

Typically, it's .022 Ohms. However, if you replace it with .05 Ohms, you can get lower current values, etc.
 
Last edited:
jander6442

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Re: BlitzBuck V3, Available Soon!

Wolfman whats the line or scratch just above the LD+ pad on theses?
 
Wolfman29

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Re: BlitzBuck V3, Available Soon!

The manufacturer couldn't handle the specs I gave it, so just to make sure something wasn't jumpered that shouldn't be jumpered, I put a scratch in all of them just to be sure. Takes away from the aesthetics, but retains functionality.
 
Fiddy

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Re: BlitzBuck V3, Available Soon!

Wolfman29 said:
Nice heatsinks! You sure it's missing a sense resistor? o.o That seems odd. But, if it really is missing a sense resistor, you can just replace it with any sense resistor you want to get any current range lower!

Typically, it's .022 Ohms. However, if you replace it with .05 Ohms, you can get lower current values, etc.
Click to expand...

yeah man, i was wondering why i couldnt get it into high mode, there was jsut no sense resistor there! it looks like it was soldered on their at one stage but it may have fell off because the solder on one of that pads was very small.

what physical size are the resistors? 8050 etc?
 
Wolfman29

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Re: BlitzBuck V3, Available Soon!

OH. You're not talking about the sense resistor. You're talking about the set resistors. The ones to set the modes.

Which one isn't there? The left or the right one? The left one should be 2050 and the right one should be 2740. They are 0603-size resistors.
 
Fiddy

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Re: BlitzBuck V3, Available Soon!

Oh ok, yeah the resistors you put the jumper across to change Hi - Lo mode.

the one on the left, same side as the IC i heatsinked.

kool ill order a resistor for it!
 
gillza

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Re: BlitzBuck V3, Available Soon!

Wolfman29,

Is there a way your buck drivers (any of the existing versions) could be modified to output 450-500mA with one cell to power a red diode such as lpc-815?

Thank you
 
Wolfman29

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Re: BlitzBuck V3, Available Soon!

The V3 could be modified to output that using the calculations earlier in this thread. Just take the potentiometer off and replace it with the correct resistor (noted earlier in the formula).
 
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