I have some questions.

[expressel]

Hi there,

I desoldered these parts from a MEGA SMPS BOARD.

IRF1405 - 55V 330W Power Dissip

IRF840A

32CTQ030 30A 25-30V SCHOTTKY RECTIFIER
42CTQ030 40A 30V SCHOTTKY RECTIFIER
40L15CT 40A 15V SCHOTTKY RECTIFIER

R860P2 - single diode for flyback use

STPS40H100CW 40A 100V High voltage SCHOTTKY RECTIFIER
IRFP450A

2x etd39/20/13

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Firstly I need to know what is the maximum Power for these etd39/20/13 trafos. I searched internet with no luck and results.
They look like big enough for 1kw each ? Is ETD49 more powerful ?

My plan is to make 2x1kW stereo class D amplifier. Or 2x500W in the bad case.

The amplifier will be single supply and i will be able to use voltage regulation.

Is these calculations right ?:

a * 8 ohm = v

a*a = 1000W/8ohm

a= 11A
v= 11*8 = 88Vrms == 124.43 Vpeak == 249 Vpp (supply voltage for the class D amp) for 1000Wrms power.

Or for 1000Wpeak -> 88*2 = 176V supply

Or average between rms and peak 249+88*2/2 == 213Vpp

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Which one from these inductors to use for the amplifier output inductor ?
And which one for the supply filtering ?

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What is better two pairs of IRF840 or one pair IRFP450 ?

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I know its not good to use big capacitors for filtering because they short circuits the smps.
How to calculate what is the maximum capacitance I can use to not short circuit the board ?

 

[expressel]

Also look at the big light bulb. Its 30V 400W one (ideal for testing 30V 400W SMPS)
or 15V 200W smps..

I have another question too -> found this site but what is the button "Coil Data"
http://schmidt-walter-schaltnetzteile.de/smps_e/hgw_smps_e.html

There are "Transformer Data" button which shows suitable cores, but what coil data button do ?

Also i need to know what is the power of the third transformer which is not from the mega board.

 

[expressel]

If my calculations are right I will be using directly 314Vdc for supplying the class D amp.(without SMPS at all)

314 Vpp == 157 Vp / 8ohm = 19,625A peak == 3.1 kW peak
== 111 Vrms / 8ohm = 14A peak == 1.5 kW rms

I need to calculate what happens at 2 ohms.

I am planning to use sziklai power stage for the amp instead mosfets because my amp design is with tl494 operating in single output where there is no deadtime.

 

[expressel]

What about 4 pairs of IRF450. They form 0.1 ohm Rds. This is 20W Pd @ 1.5kw @ 8 ohm
Im planning to drive them with IR2111 or IR2104. Is this good idea ?
My idea is TL494 to modulate the signal -> optocoupler to insulate the input -> IR2111 or IR2104 -> 4 pairs on big heatsink -> 1.5kW @ 8 ohm.
The power must be limited because at lower impedances goes higher. Its designed only for 8 ohm.

Which inductor to use for this ? I posted several ones in the first post.

 

[expressel]

There is error, I meant IRFP450, not IRF450.

Look what prototype i build but this is without opto.

This is class d amp not smps I want to know how many watts I can dissipate on this heatsink.