My first SMPS project - help needed please

[Venture]

Hi guys,

I'm trying to learn all about SMPS and have decided to make my first one. I need some advice please.

The supply is 230v AC input and about 300w total output, consisting of two outputs (48v @ 5A and 18v @ 3A). In the end i'd like the 48v to be regulated and have over-current and thermal protection but to start I can live without an unregulated design to learn about transformers etc.

I have decided on a half-bridge topology and i've had a play with the Excellent transformer design software (ver 6100). So far it looks like an ETD34 former with either N87 or 3C90 core would be a good choice, and I have chosen a 160KHz switching frequency. So, to my questions...

1. Is ETD34 size trafo okay for 300w? Am I along the right lines? Could I use a smaller trafo if needed? Is the frequency of 160KHz okay?
2. What controller IC would you recommend for a starter project? I'd prefer not to use separate controller and driver ICs (SG3525/ IR2110) but would rather a single IC for simplicity. I read the IR2153 had some problems in another persons project, or is it okay to driver mosfets directly in a 300w design?
I've seen the L6599A, which looks good, but maybe too complicated for my first project. Anyone used these? They are saying on the data sheet about the accurate 50/50 duty cycle and fixed dead time. From reading the other posts I can see this is a major problem area for others.

Any input would be appreciated. Thanks!

 

[Venture]

Can anyone help?

 

[demykiko]

hi venture,

my first smps started using the common but versatile and reliable sg35325 and ir2110
although i dont use ir2110 instead i replace only with Gate drive transfo. because the ic is expensive in our country
for the sake of first diy smps experience I follow it and gives although not yet better but good results..
my operating freq is only 50khz..and I can reach 300w maximum using only ER, EC, or EE 35 core..

 

[Venture]

Hi Demy,

Thanks for the comment. I know that SG3525 and IR2110 are a good combination but that combination just seems a little old and clunky. I'm looking for one IC that can do both the timing and gate drive but I've heard people have had problems with the 2153. Just wondering if there are any other ICs out there which are simple to use.