Making car amplifier SMPS with tl494 + DC Protection

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2pist

2pist

Member
Joined 2004
aliazhar said:
true, but, i dont think that guy's email address is valid anymore...

his server does'nt exists anymore :)

so, i have to figure out a way...


or wait for some more advice from here.
Click to expand...

I did Get a hold of Matt through the Forum email link at the bottom of his post. He still has torroids available. They are super efficient. The primary has 3mm of wire (soldered end) using 6 strands. secondary has 2.5mm using 4 strands for each winding.
 
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aliazhar

Member
Joined 2008
2pist said:


I did Get a hold of Matt through the Forum email link at the bottom of his post. He still has torroids available. They are super efficient. The primary has 3mm of wire (soldered end) using 6 strands. secondary has 2.5mm using 4 strands for each winding.
Click to expand...


thanks for the info....as i mentioned earlier, i have already ordered toroids....so, I will have to check them out first myself before order these...

to tell you the truth, buying something will kill the whole fun of DIY ! :)

Thanks again!
 
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aliazhar

Member
Joined 2008
since i am waiting for toroids, i thought, 'lets try again with this SMPS till i get toroid'...and got some positive results...

I had another E-Core from Magnetics, which i have bought from surplussale....

first the winding:

1.7mm wire = 2x 4-turns (4-0-4)
0.4mm wire= 6x 16-turns

test results:

Idle amp usage: 200 miliamp

Load:
36v 3amp = 108 watt

battery amp use on the above load= around 12 amp ( ~ 140 watt)

Thermal condition using a normal heatsink of 1"x1/2"x4" on each side:

on the above load, it gets a little warm after about 6 minutes.



now, do you guyz think that its a good result?....
i am using a standard schematic from this thread with 4 mosfets in total.

mosfets used are: STP80NF06


please post your opinion on these results.
 
luka

luka

Member
Joined 2005
classdaudio.eu
Hi

More wire more current yes and no, since skin effect comes into play here. Do you have any wire close to 1mm, which should be good to use, and if you do have, use 4x1mm for each primary, 2x1mm or what you have just more wires for each sec...with usage of large core this should be good for 1kw, so have I been told

with toroid you remember that each winding, pri or sec must be spread on whole core (primary, where it starts, there should end, or very close, after making one turn), same for sec, which can do more turns
 
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aliazhar

Member
Joined 2008
ok....re-checked everything...found a short at the output...my fault...sorry.


now after that, i have tested it with a 100watt load...

here is the test:

smps output voltages: 44.5

output load: 100w (17.5v 5.5amp)

voltage drop: from 44.5v to 39.5 volts


now, the question:

1. why there is a voltage drop, when i have a regulation?

2. one side of the mosfets is getting a bit warm...and the other is normal temperature....why only one side is warm?....

Thanks again for all your help !
 
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aliazhar

Member
Joined 2008
ok...after reading/searching the forum....i did some experiments....

and now the output voltages are 99.99% precise....not even 0.01 volt drop !!!!

initially, this circuit was working at 63Khz....so, I have reduced the pwm to 25khz....and added about 10% addition in the secondary winding...


by doing that, voltages are stabalized and i dont see any drop at all.

I am now, ready to increase the number of mosfets to total 12 as Perry advised and then will post the results.

Thanks again everybody !
 
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