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FrozenGate by Avery

Planning DIY TPS63000 based driver

Im off the clock now @ work ... time to stuff one :)
... and see if I let out some smoke ...
 





First attempt .... FAIL :(

At least it was a total fail, which leads me to believe that it was a poor reflow and not a design issue. Ill try again tomorrow.

 
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Rafa said:
What is wrong with that board?
Click to expand...

Its not even starting up, showing 0 current from either a fully charged 18650 or a PSU. Also using solder paste without a stencil is tough ... I couldn't get to work today, but ill try the regular solder method on Monday.
 
Replaced the TPS, inductor, and Amp and managed to get something out. It starts at about 30mA and slowly goes up to about 60 before shutting down completely. Maybe 1.5uH is not enough inductance?
 
oooh I see. hope you find out what inductor to use!
waiting anxiously for news of the TPS driver :)
oh, and I want my POT! >)
 
Well I ordered some 2.2uH and 3.3uH to see what that does. They should be here on Thursday.

(did you not see the pot in the pic above?:whistle:)
 
jib77 said:
Comming soon ...
[/img][/url]:drool:
Click to expand...
Looks very interesting:drool:!
By the way - if you would like to get a practice on BGA soldering, it is very useful to take some old / broken mobile phones and use their PCBs and IC as a sample, trying to desolder and solder them back. Better to use live mobiles to check, if it powers on after surgery:whistle:
The best result in BGA reballing were received using ready balls, like this:
BGA Balls on Ebay for $3.00 only
The balls are soldered to IC chip using the template:
BGA template.
Hope I'll find it useful....
 
It's been a long time, I know, but huh... I'm fried with work and more work...

Yesterday I managed to test your TPS63000 drivers. Charging it with a 3V load and giving 4.1volts to it, it had a 100mV voltage ripple... but almost 200mA current ripple. With a 5V load, the results were .5Amps of current ripple with a very strange waveform. It was oscilating from 300 to 800mA, with a .4 volts voltage ripple. My temperatures were about as yours, like 40ºC
I'm gonna try them with a different testload (a CREE XR-E LED) in the near future because I suspect that my test load might be broken or something (or at least i wan't to be sure it isn't). And i'll have to test them with a battery too.

Anyhow, based on pictures, lavadrives include a couple more capacitors in some places that are most likely related to feedback voltage filtering. I think those capacitors aren't random and that they are responsible for having such a clean output. I'm pretty sure that designing a driver with a differential amplifier requires some maths and some loop stability analysis.
 
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jib77 said:
Well I ordered some 2.2uH and 3.3uH to see what that does. They should be here on Thursday.

(did you not see the pot in the pic above?:whistle:)
Click to expand...

haha, I did see. I just hope that you do not remove the pot for building a more stable driver :)
 
Oh, forgot, it's likely a short-circuit under the coil. Those XFL4020's come with a ton of solder in their pads and if you put too much paste, it forms a ball under the coil and shorts it. The solder they have is also pretty fluid for some reason, and the coil can't stop moving under the hot air current. I hate them but... it's what we have.

1.5uH should be just fine. I'm doing my TPS63020 experiments with 2.2uH just because coilcraft hadn't 1.5uH XFL's in samples stock until some day in 2011, but according to TI's Switcher Pro simulator, 1.5uH should be just fine for this application
 
Think adding a .1uF bypass cap to the FB via would help?
4357-fbbyp.png
 
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