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Switch mode power supply build

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Enzy

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https://www.ebay.com/itm/182307479849

I bought this amplifier board from ebay and it needs +/- 75V and I have a Ecore transformer to be wrapped and I have foil winding, even though I have never used foil winding but I wish to learn, the part that I think is most complex is for getting a working circuit, which I know smps circuits are complex, but I'm not looking anything overly complicated but I would love to build one.
 

Hi,

The only value you give is +/- 75V.

For transformer calculation you additionally need
* converter mode
* CCM, or DCM
* output current
* input voltage
* switching frequency
* core size and it's magnetic parameters
* core air gap
* maybe other values

But before you focus on the transformer you need to study the various SMPS techniques.

Klaus
 

Based on my reading the voltage control method would be the simplest, so Voltage control method, Im not sure how the circuit will be designed but as I said I want 75vdc but @1000W s thats about 13.3amps I dont know what the transformer inputs and outputs will be since I dont know how to design the circuit, switching freqency just the same.

I dont need state of the art I just need something good enough to work.

I had a E-80 core and a roll of 0.1*200*5000mm foil winding

Core Specs:
Dimensions for each half:

AL = 5000
µe=1890
A: 80mm (3.15")
B: 59mm (2.32")
C: 38mm (1.50")
D: 28mm (1.10")
E: 20mm (0.79")
F: 20mm (0.79")

see pic
 

Whilst edaboard is the best power supply and electronics forum in the world, because you specifically want an audio power supply, and are a beginner, there are millions of people whove already asked that on diyaudio.com......there are mutliple posts where the thing is fleshed out there for you....come back here for detail though as theyre not quite as good at stuff as this website.

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anyway, is it an type D amp?....if so then peak power is far less than average power and you can make savings.

It sounds like you coudl use a full bridge in current mode......the output inductors will need coupling for best output cross regulation....but if you do do it in voltage mode, then the output inductors dont need coupling. Voltage mode isnt very common nowadays, it brings up resonances in the power stage etc that you have to deal with.

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here attached is my report on a full bidge with split outputs like your require...its only 330w peak though, so you need to scale up
 

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  • PFC'd Full Bridge SMPS _330W.zip
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Ok thanks for the schematic Ill look into it when Im at work and yes its class D 1000w is only @2ohms, 600w 4ohms ill work with the schematic even just for practice.
 

OK, but if I may guess at your situation…as this is common for people starting out in class d power supply…So, you want a power supply for class d, and you were going to buy off the shelf, but because the average power is so much lower than peak power, you think you can do a cheap power supply custom build yourself(?). Also, most off the shelf power supplies have fans in them and you don’t want the noise of a fan.
If it’s the fan, then maybe just remove it and use off the shelf…as long as you don’t overheat then its ok……or just pick a quiet fan and use that near it instead of the internal fan…….or just have the fan come on when loud music playing.
You cannot really massively downsize an smps if the average power is much less than the peak,……because you must respect the ferrite saturation etc etc…I suppose you can reduce heatsink size though.
Other point is that people often don’t like the no_load_to_full_load transient response of off the shelf power supplies for class d supply…as off the shelf offline PSU’s often have opto feedback and are very sluggish…….if that’s the problem then why not have offtheshelf for the mains connection, and then use your own (or bought in) DCDC after that with a faster feedback loop to give you your fast transient response.?

Attached is a document about offtheshelf psu's for class d guitar amp supply
 

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  • Off-the-shelf PSUs.doc
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That's good info, I actually want to learn how build them for myself so what I did was to buy an amplifier) class D. I have bought class d amp on more than one occasions but I normally build linear power supplies which was normally less in power and it normally makes the project heavy because of the transformer and I need to eliminate weight, but I love electronics and I thought myself so far how to design pcb boards even though I wouldn't say I'm good at it but they work to a level and I'll improve.

But my aim is to build smps circuits for myself even if for now I just have a basic design and I would just make different transformers to get different output voltages, I doubt that's recommended but if I start their then I would get a better understanding then I can improve more and I'll be able to better understand the things I read

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Buying electronics is easy fore but in my country clearing them at the customs isn't cheap, it's normally the price that you paid for the unit, it's cheap for me to buy cores online for various projects and buy components online in bulk from China my boards I can buy copper clad boards or send designs to China to get boards build.

With amplifier circuits im young so I normally go by the basic diagram shown in the data sheet for audio Ic's and build linear power supplies but for such small circuits the weight too much and the power supplies are bulky and isn't of much power and in my country I can get more than 10amps in ready made transformers and they normally. Only have them in 6-0-6v and 12-0-12v which isn't helpful to me at all.
 

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