Boost Converter 4.5VDC-330VDC / Electromagnetic Projectile Accelerators / Forums

Forums

4hv.org :: Forums :: Electromagnetic Projectile Accelerators

« Previous topic | Next topic »

Boost Converter 4.5VDC-330VDC

first previous 2 3 4 5 next last

Move Thread

LAN_403

voyagerscout

Tue Sept 16 2008, 06:35PM

Registered Member #1696 Joined: Sat Sept 13 2008, 06:01PM
Location:
Posts: 21

Have you got any idea where to buy a 130 uH inductor? I have been searching for hours and so far I only found 150 uH and 110 uH.

Killa-X

Tue Sept 16 2008, 07:32PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

voyagerscout wrote ...

Have you got any idea where to buy a 130 uH inductor? I have been searching for hours and so far I only found 150 uH and 110 uH.

I found a 120uH and he told me it should work..

Firefox

Tue Sept 16 2008, 08:21PM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

Ummm, the inductor isnt -that- critical. You can use anything from 100-300uH. Less or more if you understand how to adjust the circuit properly. Using something in this range just keeps the size small, so you can keep the circuit small.

aonomus

Wed Sept 17 2008, 02:03AM

Registered Member #1497 Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801

Keep in mind that the inductor is only a energy storage piece, the important part is that your MOSFET is rated to take the voltage/current produced if you put in a big inductor.

Steve Conner

Wed Sept 17 2008, 10:12AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

And that in a nutshell is why the boost converter sucks. You need a MOSFET that can handle the input current and the output voltage. Say you wanted a 10 watt boost converter that went from 5V to 330V: You'd need a 2 amp, 330V MOSFET.

If you used a flyback transformer with a 1:10 ratio instead of the inductor, you'd only need a 2 amp, 33V MOSFET, and a 0.2 amp, 660V diode. The 33V MOSFET will be cheaper, and have much lower Rds(on) than a 330V piece too, so you win twice.

Killa-X

Wed Sept 17 2008, 05:10PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Dr. Meh wrote ...

And that in a nutshell is why the boost converter sucks. You need a MOSFET that can handle the input current and the output voltage. Say you wanted a 10 watt boost converter that went from 5V to 330V: You'd need a 2 amp, 330V MOSFET.

If you used a flyback transformer with a 1:10 ratio instead of the inductor, you'd only need a 2 amp, 33V MOSFET, and a 0.2 amp, 660V diode. The 33V MOSFET will be cheaper, and have much lower Rds(on) than a 330V piece too, so you win twice.

I'd be using Uzzorz booster with maybe just around 6-9V about... So, I the MOSFET he picked should be the right one for that.

j.azz

Fri Sept 19 2008, 02:26PM

Registered Member #888 Joined: Tue Jul 10 2007, 06:52PM
Location: Hannover, Germany
Posts: 40

What about supplying the rectangle pulse to a 'normal' transformer? I don't know if that's going to be efficient and may have the same problems as with the boost converter as the pulses are injected to an inductor(primary of the transformer) as well.
I use to charge my caps with a setup like 230->12->360 Volts with transformers(not portable of course).

Firefox

Fri Sept 19 2008, 05:47PM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

If you can find a small iron-cored logic supply transformer, you could drive it with 70 or 80 Hz square wave pulses from a 555. I've used this method with a 120-24V transformer driven with 12V to produce a 60V output.

Killa-X

Sat Sept 20 2008, 01:36AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

I still wanna know how strong this transformer is that I got from a toy. It rips 6V from the batterys, and is able to power a 1cm wide, 5 inch long florescent blacklight. The transformer it self is over 1X1X1 cm. I really want to know how much it can do. Recent googles show u can run it with just a 555 timer.

uzzors2k

Sat Sept 20 2008, 10:07AM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

youngcoilgunner wrote ...

as someone in an earlier thread in hv forums once posted, a boost converter is limited to charging to 20 times its input voltage.

Wrong. My boost converter runs from 12V and charges to 450V, that's nearly a step up of 40. There's no reason the boost converter topology's voltage gain should be limited by anything other than it's loading.

The boost converter isn't ideal for capacitor charing, but everyone who cares knows this already! The reason people keep building it is because it's simple to construct, uses a 555 which people have from their flyback driver projects and also requires a minimum of components. And above all there aren't any chargers out there which are more noob even if people wanted one. The design could complicated and improved in so many ways it could match a DRSSTC in complexity, but then nobody would build it or I would be flooded with even more help requests.

Killa-X, I would guesstimate it to be only good for a few watts.

first previous 2 3 4 5 next last

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob