new boostconverter design

Lomy, Sun May 20 2007, 11:28AM

hi guys,
because i never have some functional ne555 ( im a real ne555-killer ) i started to think about a new idea to creat a signal for a mosfet. and then i got a idea : i built a multivibrator which creat the signal. it works at 12v having a frequency of ~4khz and a dutycycle of ~70 %. i got max 30 watt out of it with a mosfet out of a tv and i used a bit more then 12v mistrust . but soon a will have some irfp460 again and then : time to rock output : ~ 500v with a irfp460

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perhops u have some ideas to otimize it. POST them fast and tell me wot you think about this booster


[Edit: Image size maximum 400 pixels]
Re: new boostconverter design
killerbanjo, Thu May 27 2010, 02:38PM

Looks great. Tryed it out in falstad's sim and it worked good!
Re: new boostconverter design
hboy007, Thu May 27 2010, 03:37PM

>> POST them fast

"The ability to wait for something without getting angry or upset is a valuable quality in a person". tongue

the rising edge of the saturated multivibrator as you built it is rather slow. Maybe this generates soft switching characteristics but you could add a schmitt trigger that makes the rise and fall times shorter.

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The BC547/557 combination has good current gain but the maximum output current isn't that large. Maybe you spend another two transistors on a BC635/BC636 pair, they can handle 1.5A peak.

Once you've fixed that you can further increase the pulse width but things won't be worth it once your storage choke saturares... no current-mode control, no feedback, what are we expectiing, anyway?
Re: new boostconverter design
Lomy, Sun Jun 06 2010, 07:58PM

forget about that crapy kind of stuff i built 3 years ago =D. if i would build something like that today, i would use pic or atmel UCs =). combined my 2 big hobbys, programming and electronic, today im building robots or other cool stuff =D

like my 2 player game console, running pong or trone:

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