Transformer design

Your specifications look like a mix of specifications for a switching supply (which includes a transformer) and a transformer (which is an iron or ferrite core with a bunch of wire wrapped around or through it).

Which are you looking for?

Transformers for switching supplies are generally custom made, and are either designed by the circuit designer or are designed with a great deal of input from the circuit designer. This is because there are some sharp trade-offs between switching frequency, transformer size, and circuit efficiency.

Transformers that run off the power line (120V or 220V, 60Hz or 50Hz) are stock items, but only if you're talking about the 'normal' 50-60Hz line frequencies.

Switching supplies can be had to the specifications you state (just do a web search on switching supplies), but you don't generally get to specify the switching frequency -- often you don't even get to know what it is, unless you do some digging.

Rahul,

Your input voltage range is probably too wide to be effectively transformed by the forward topology. It's not impossible, just bad design.

You have two immediate options for wide range input above 200W, one is a power factor correcting boost input stage, the other is a simple switched voltage doubler that would allow operation over the range of 90-135 or 180-270VAC.

This is what most commercial products employ at this power level. At lower power levels, a flyback topology can handle a wider input range than most others.

RL

dear sir can you send above design in flyback tech. with 180-270VAC

skrev i en meddelelse news: snipped-for-privacy@d21g2000prf.googlegroups.com...

Yes I can - but I won't!

From the old Unitrode seminar's, theres a 150W discontinuous conduction mode design example for the narrower input voltage range. For 180-270V you apply the input voltage to the 230V schematic connection.

You can fiddle around with the numbers yourself to see what happens when larger power levels are expected from the topology, or the input voltage range is extended.

An earlier article looks at transformer sizing for this topology.

Check out a later article to predict the effects of leakage terms, as the power is increased, continuos conduction mode is entered, or other physical features are altered.

Many other articles are available as application notes on the web, some with board patterns and magnetics information.. The problem with a schematic alone is that it will not contain sufficient information on function, never mind construction, of the practical circuit.

RL