SMPS for Class-D amp.

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plasma

New member
Hi everyone, :)

I am building a Class d amp (almost finished) which needs +/-60V at ca. 800W
I tried some regulated designs but they didnt work well (driving the mosfets with GDT's)...
So i thougt about a unregulated design with IR2153, IRF740 and a ETD49 core.
Is it possible to realise it with this parts?
 
N

norazmi

diysmps Senior Member
well take a look at power supplies and smps forum, there are many design which can provide 800w peak, ir2153 feed with irf740 at 800w peak to peak with non stress all the time can be accepted, but irfp460 is better, make sure aux supply for ir2153 is enough 200ma or it will be hiccup at peak power. high rail caps need to be at least 1000uf 200v x 2 or better 4 pcs. etd49 core is enough with 80 khz freq and use multi stranded wire for primary and secondary. which class D amp you want to run with?
 
P

plasma

New member
I have a lot of 1600µf 330V photoflash caps here, i think 2 are enough.
The class d is my own creation ;) if you want i can post some pics.
 
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norazmi

diysmps Senior Member
yea systemjol is correct, where is filter caps at P$10? without it, it will be fireworks happens.
 
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plasma

New member
Well, fu** :(
i forgot it, and today i made the circuit.
but i think there is place for that cap.

is 1 µf enough?
 

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P

plasma

New member
It works, i didnt test with more than 300W but, up to this power the mosfets dont need any cooling^^
the only problem is, that the circuit is oscillating at 50Hz, when i connect the output with the ground. I think its because of a feedback with my protection circuit.
so i removed the tansistor that switches of my 2153, so now its working, but without protection...

IMAG0040.jpg
 
P

plasma

New member
Yes, the last pic is the the final version of the SMPS...
The onlx test i made, was with the complete amplifier driving two 4OHM 350Wrms/600WProg speaker at full power, for nearly an hour...
after the test, the warmest part of the circuit was the print-trasformer xD ...
 
P

phoenix

New member
how to winding

plasma said:
It works, i didnt test with more than 300W but, up to this power the mosfets dont need any cooling^^
the only problem is, that the circuit is oscillating at 50Hz, when i connect the output with the ground. I think its because of a feedback with my protection circuit.
so i removed the tansistor that switches of my 2153, so now its working, but without protection...

View attachment 3915
Click to expand...

plasma: How to P and S
windings
 
K

KX36

New member
LM358 is an opamp where you really should use a comparator. Also since IRRC it has a totem pole output you can't just connect 2 outputs together and expect them to OR together. Since a totem pole can either source or sink current, you open yourself to the situation that one output can source current into the other essentially short circuting the power rail across the opamp (albeit with some protection from within the opamp). Not good for opamp or power rail.

That whole section of circuit is obviously meant to use open collector comparators. Try LM393.

I haven't bothered looking at the rest of the circuit in any detail.
 
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