Suggestions for DC Power Supplies

[abicash]

Hi,
I have a requirement which demands use of a very low cost DC power supply for a stationed unit.I have a 12V with not more than 200mA max current requirement.
I could use a standard Transformer-rectifier-filter-regulator(7812/317) but the catch is "VERY LOW COST"
I am thinking of using DC-DC converters..but will it keep the costs down?
Is it really possible to keep costs very-very low (maybe<20cents)
I want some suggestion here,if it can really be done?
Thanks for any pointers in advance

 

[meitolake]

The transformer is a major cost. Is it necessary?

 

[cristianp]

What is the voltage input?
For 110VAC/230VAC you can use offline power converters that are used in low cost power converters.

 

[abicash]

I think transformer can be eliminated.Only that isolation is poor.I wanted to know whether a 200mA load can be driven.People use it for smaller loads (<15mA)
Take a look at this
or this

My requirement is
Mains i/p=230V/50Hz
O/p=12Vdc @ 200-300mA

 

[meitolake]

If the transformer can be eliminated, you can use a capacitor for step-down. Be careful, lack of isolation is dangerous! And, you can use some discrete components to replace the 7812 or 317 for low cost.

 

[Candy8866]

pls check the link:**broken link removed**
maybe it is useful for you

 

[abicash]

Hi thanks all for the tips...I am close to cracking it and this month I would be using that in a project

 

[mahgoub]

The transformer is a major cost. Is it necessary?

 

[abicash]

Hi all,
So working more on my project,I have cut down on most resources and peripherals.
I require now
5V@50-60mA
(or even lesser)
My actual load is a 5V relay,a small Freescale microcontroller and a Vishay IR detector.So really the most power consuming part would be the relay,which I am still looking for a better volume price.

My customer requires power dissipation <0.5W,and I cant see a TL431 ckt or directly using mains with an RC taking me anywhere with substantial Power dissipation.Power dissipation has to be <0.5W

I cannot use a transformer too..since the project has to be <$2 and that including the power supply
So anymore help would be appreciated.
Thanks and regards

 

[abicash]

Hi
I almost forgot to mention all these days about a wonderful device which I have used for my xmerless power supply from Power Integration which has substantially reduced my power dissipation and cost.
Check this **broken link removed**

I can get good currents (up to 300mA @5V).Although its not isolated but its the same thing I needed!