52613 sfw356645eh5ah6j75
Member
well still with my "ultimate" fan controler, i saw that using pwm to control capasitive loads is a big no, so desided to use a buck converter, but as p channel mosfets arround here aren't big enough, i decided to use a n channel one and instead use a flyback converter, and btw add overvolting capability.
the thing is i need something to take 12V and output from 0 up to 40V, with reatively high eficcience.
say about 16A @ 12V.....about 200W, i need to make 3 of these, so they have to be rather small, and the power limit is in general between the three.
The voltage contro in done by a micro that i already programed and all, so the only thing left for me is this.
But i couldn't find much about good practices and formulas to make a smps of more than 1-2A.
i made a few tests with the transformer from an atx psu, originaly it worked at 50khz but in some tests i had no problems switching at 500khz and the efficiency went a little bit higher. but even with little load efficiency was horrible....and the mosfet got warm with less than 500mA, (i did everything i knew right yet the secundary doesn't seem to discharge properly, so the mosfet's diode takes the rest...).
also made my own toroid.....u.u
i'm missing a lot of knowledge here so info, what should i look at, where, or a better alternative, whatever that could help me would be really apreciated as this is the only thing holding this proyect.
also the pwm control i made works like s*** (triangle > opamp > 555, with another opamp controling the one that generates the output), and the coil starts making noise even though the voltage stays stable.
don't know where else to look, thanks in advance u_u
the thing is i need something to take 12V and output from 0 up to 40V, with reatively high eficcience.
say about 16A @ 12V.....about 200W, i need to make 3 of these, so they have to be rather small, and the power limit is in general between the three.
The voltage contro in done by a micro that i already programed and all, so the only thing left for me is this.
But i couldn't find much about good practices and formulas to make a smps of more than 1-2A.
i made a few tests with the transformer from an atx psu, originaly it worked at 50khz but in some tests i had no problems switching at 500khz and the efficiency went a little bit higher. but even with little load efficiency was horrible....and the mosfet got warm with less than 500mA, (i did everything i knew right yet the secundary doesn't seem to discharge properly, so the mosfet's diode takes the rest...).
also made my own toroid.....u.u
i'm missing a lot of knowledge here so info, what should i look at, where, or a better alternative, whatever that could help me would be really apreciated as this is the only thing holding this proyect.
also the pwm control i made works like s*** (triangle > opamp > 555, with another opamp controling the one that generates the output), and the coil starts making noise even though the voltage stays stable.
don't know where else to look, thanks in advance u_u
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