Help me choose topology for SMPS design

Hi ,
I want to 1 KW implement a switching power supply,
with typical output DC voltage of 28 12 and ..
where Can I start from?
(I am new in the field!)

Regards,

split-pi schematic

is it mains fed.....? or battery?

you will need a power factor corrector for mains fed.

then say a full bridge would be good.


Get a PWM chip with the features you want and go on from there......

schematic smps 2 ir2110

it's a mains fed,

my main problem is which topology to use?
I need buck-boost, Highly efficient design , with multiple output voltages.

Why a full bridge?
what about split-pi or "resonant zero voltage" switched ?

Regarding this webpage: https://en.wikipedia.org/wiki/Switched-mode_power_supply
I selected split-pi since it has very high efficiency but i'm not sure if it is really ok?
I don't really need a bi-directional supply! but i need a highly effiecent one,

Thanks

split-pi circuit

The split-pi topology does not contain any special properties, which makes it more efficient than any other topology.
So do not choose it simply because Wikipedia recommends it.

Based on the information you have supplied I would go for the full bridge as well. It can be made to provide high efficiency and it is the logical choice to the power level you need.

Depending on your application you may face a requirement of providing a high power factor.

It (the full bridge topology) too can be made as a resonance based converter and/or with zero voltage switching.
However choosing either or both sub-types usually means that the high efficiency only occurs at a limited power range of you choosing.


Cheers,
/Ghydda

smps full bridge schematic

Hi, again!

Does any one here know of a practical 1KW full-bridge schematic with relatively high efficiency (>85%)?
I found that it's no way easy for me to design it myself!!

Regards,

full bridge smps

if its all new....think about a straight bridge design....

just 4 switches....yuo dont have to isolate...use high side boost level driver IC's...eg sumthing liek IR2110....

i think you need to start with a bridge driver IC and then get its datasheet..then the applcation notes relevant to it..

none spring to mind...or is it SG3525?...i forget

but the app notes are usually best.

smps full bridge

Hi
Take a look at darla1 post, this contains a schematic which will give you a head start with a full bridge design, there is an error in the phasing of the parallel fed driver transformers which you will need to correct, the windings on each transformer should be opposite phase for each side of the bridge, not as shown, but this circuit seems to work according to the thread.
You will have to design your own custom magnetics of course, this is not easy but as noted by other contributers, there are lots of app notes out there to help.



85% efficiency is not very easy to achieve at this power level, you will certainly need to look at synchronous rectifiers to get near to it, the above circuit does not use them incidentally.

Best regards,
Bob.