I need an circuit design for switching power supply, the circuit should be something like the PSU of an computer, with NTC protective thermistor etc.
Are some interesting websites and documents/books on the internet about switching power supplies.

 

You might want to start by defining some requirements. For example start with some estimates on input power, efficiency, and output power. This set of values will set your expectations and drive to component selection process.

 

Or you could buy one. Someone else has done all the calculations, selected suitable components, laid out the PCB, made sue it meets EMC regulations, sized heatsinks, etc. It would be much quicker, cheaper, and more reliable than tying to do it yourself.

 

I want to make with own specifications. It's for hobby/home use.
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It should have high efficiency (80-90%).
Input: 120V 60Hz and/or 220V 50Hz
Output: 12V, about 4-5A.

 

I want to make with own specifications. It's for hobby/home use.
----------------------------------------------------
It should have high efficiency (80-90%).
Input: 120V 60Hz and/or 220V 50Hz
Output: 12V, about 4-5A.

You've specified an AC to DC conversion. For a buck-boost converter you need to specify a DC input range. This range will include the output voltage of +12VDC. Then we have 12VDC times 5 Amperes = 60 Watts of output power. At 85% efficiency you'll need 70.6 watts of input power. Let us say your input range will be +4VDC to +18VDC. At +4VDC, 70.6 watts will require 17.64 Amperes. The inductor in your buck boost supply will need to be able to handle twice that current or 35.3 Amperes. At +18VDC things are much better; you'll only need 3.9 Amperes on the input and twice that or 7.8 Amperes in the inductor.

How you factor the mains supply into this system is a secondary problem. You first need to figure out how you're going to use the solar output to charge the battery. Or did I miss something?

 

I want to make with own specifications. It's for hobby/home use.
----------------------------------------------------
It should have high efficiency (80-90%).
Input: 120V 60Hz and/or 220V 50Hz
Output: 12V, about 4-5A.

Don't waste your time, just buy a ready made one....