SMPC Help: Basic Questions and Understanding

Hello,

I am looking to build a SMPS to power an audio IC. I require a stable 50v output voltage from a 12v (10v to 15v really) input. What complicates this, is that I need about 1800W output maximum. Probably closer to 200W-300W on normal occasions, however the design must satisfy the worst possible case.

Space is not really a concern, but component cost is. So some questions:

1) Should I split the design into multiple stages to lessen the harshness of the switches? This is an audio application and the worst thing would be for the switching frequency to wind up in the audio signal. If I do split it, are there general guidlines for doing so? Like increase in powers of 2 or 3 or something?

2) To get a good 50v output, should I go above 50v, then buck it back down to 50? Or do you buck the input down to 10v and then boost it up? What is the best way? Efficiency is great, cost is better, but noise elimination is king.

3) Are there any cons for an isolated design? Am I correct in that an isolated power supply will reduce or eliminate noise fed back into the original supply line?

4) What are the advantages and/or problems with splitting the power supply into multiple identical blocks? Meaning can I make 3 identical SMPS's with maximum outputs of 600W, and then tie the grounds together but have the + outputs connect to different circuits and not together.

5) What about minimum load current? If I need a design that outputs such a high maximum power, what happens when it only draws a few watts?

I would really appreciate any help on this.

I am not familiar with your application, but just looking at what you want the converter to do, I would look at possibly using an isolated full bridge dc-dc converter. The stress on the switches is low, and it can handle the 1800W worst case output power. I would think building three other converters would just complicate things and probably end up making you spend more money anyways.

Thanks for the feedback.

I have been playing the the epowersim designer and it seems pretty nifty. Has anybody used one of the designs it auto-generates to see if it actually works?