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Boost driver ideas...

W

woop

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inductors step up voltage using the 'flyback' property, when you charge an inductor and then disconnect the current, the magnetic field in the coil collapses and the change in magnetic flux produces a high voltage spike.

if you have ever had one of those trick shocking pens, they have an inductor which is connected and disconnected to the battery repeatedly, and they produce voltage spikes which shock you
 





A

airy52

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are you talking about the zetex toked? anyways no one explained what it was used for in this circuit. stepping up voltage? or what i gathered from wikipedia it could be a "choke?" that, in conjunction with a capacitor, takes out hum and fluctuation's in the voltage...?... :eek:
 
W

woop

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airy52 said:
are you talking about the zetex toked?    anyways no one explained what it was used for in this circuit. stepping up voltage?     or what i gathered from wikipedia it could be a "choke?" that, in conjunction with a capacitor, takes out hum and fluctuation's in the voltage...?... :eek:
Click to expand...
the inductor produces high voltage spikes, and the capacitor smooths all the spikes out to get DC
 
A

airy52

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why would you want it to spike and then have to smooth it out? just take it out and it wont spike? are you using ac or something? sorry to be a complete retard, once i get something, i get it and dont forget it. youre helping a lot.
 
T

toked323

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airy52 said:
why would you want it to spike and then have to smooth it out? just take it out and it wont spike? are you using ac or something? sorry to be a complete retard, once i get something, i get it and dont forget it. youre helping a lot.
Click to expand...

The capacitor will smooth it by makeing it a certain Constant Voltage instead of a bunch of high spiking voltage.

ex. 20v spikes with cap 10v smooth
 
A

airy52

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alright i completely understand now i read a little more. the chip cannot just do it by itself, inductors are hard to incorporate into semiconductors, so they make you add your own, and so you can change it. its required for the chip to work and thats how it works, thats why its called a switching power supply, it switches so that the inductor spikes a bunch and the capacitor smooths that spike out. im sure you already know this its just for anyone following this. Thankssss!!!!
 
W

woop

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airy52 said:
alright i completely understand now i read a little more. the chip cannot just do it by itself, inductors are hard to incorporate into semiconductors, so they make you add your own, and so you can change it. its required for the chip to work and thats how it works, thats why its called a switching power supply, it switches so that the inductor spikes a bunch and the capacitor smooths that spike out.  im sure you already know this its just for anyone following this. Thankssss!!!!
Click to expand...
yeah. thats about right :p
it is a bit hard to explain

you want to make spikes with the inductor, so that you can get more voltage, thats why its called a step up converter.
 
W

woop

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toked323 said:
Well, I was bored so i made a resized image of your circuit woop, Its at 13% which was best for me in printing
Click to expand...

that's a bad idea. that image is TOO small. the feedback track is shown as touching ground and pins are touching.
its better just to print it at 13%, then the print won't lose any resolution, by resizing the actual image you have lost resolution.
 
A

airy52

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resize it but change the dpi. but then you have to change it back for the printer... so just dont resize it.
 
pocketfluff

pocketfluff

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Hey I just put together my lm3410 sepic. Its pretty big but it works! I forgot to put in the 100k resistor between Vin and DIM so it did not work at first. Then by some freak accident my finger connected those two pins and it lit up ;D

Time to revise my board....
 
J

jaap75

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Sep 17, 2007
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Hi,

I'm trying to built this cicuit, And i found a guy who can supply the SMD parts for me.
Only witch size is the best: 0403/0603/0805 or 1206?

And he also has got 10uH smd coils with the following diamentions: 5,6x5x5 mm
Is this to big?

Please let me know,
Regard. Yoeri
 
rkcstr

rkcstr

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jaap75 said:
Hi,

I'm trying to built this cicuit, And i found a guy who can supply the SMD parts for me.
Only witch size is the best: 0403/0603/0805 or 1206?

And he also has got 10uH smd coils with the following diamentions: 5,6x5x5 mm
Is this to big?

Please let me know,
Regard. Yoeri
Click to expand...

0403 is going to be very tiny, 0603 pretty small as well... If you can fit it, I'd stick with 0805 or 1206 (depending on your power needs), as they'll be easier to work with, unless you feel confident you can work with the smaller ones (take a look at some specs on them, get an idea of their size).

As for the coil, that sounds like it would be small enough for this application, but you have to make sure the DCR is low enough and the current handling is high enough (which I'm not sure what the requirements are).
 
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