PSU Reference Design Recommendation

Posted by: russm1981 on 11/22/2013

Hi,

I currently have a product which uses a miniature embedded power supply (e.g. Mornsun LS03-R2 - see attached datasheet). This works fine for my application - I need about 5V at perhaps 400-500mA - but I'd like to reduce cost and improve layout (an embedded unit reduces my layout flexibility).

I'd therefore like to design my own supply based on one of your designs.

It's for a consumer product, hence:

> Need to meet all the US and EU safety standards

> Need to meet strict EMC - e.g. EU Class B for domestic use

I only have 15mm height above the PCB available.

Can you recommend a reference design which would meet these requirements and be simple to design? In particular I am interested in the difficulty meeting EMC requirements.

My final cosntrant is the need to isolate my low and high voltage components. At the moment, I acheive this by keeping all the high voltage components surface mount on one side of the PCB. Will this be possible with your designs - e.g. are surface mount capacitors and transformers available?

Finally, can I assume the 1.6mm PCB thickness will provide sufficient protection to meet safety standard between low and high voltages?

Many thanks

Russ

Files

Power Supply - Morsun LS03-R2_EN.pdf (403.41 KB)

Comments

Hi,

What is the input voltage range of the power supply?

For you concerns of safety and EMC, there is absolutely no constraint from PI parts to be able to meet the US or EU safety standard and EMC Class B. You can find many of our reference designs that meets these requirements. Since the power range of the PSU is about 2W or 2.5W, I am quite sure you can use the SMD components for you design.

Hope this is helpful

Thanks

Terry,

Thanks. It would be the full US-EU range so I guess 100-250V.

I can obviously replicate your reference designs quite easily. However, how critical is PCB layout to their EMC performance etc. If I replicate your design using basic good practice (e.g. locating coupling capactiors near components) etc, then am I likely to meet the domestic requirements easily?

Also, do you have any guidelines on what's required to meet various safety standards? Recommended track spacings, widths etc? Also, is a 1.6mm FR4 pcb good to isolate a mains signal on the top layer from a low voltage 'safe' trace on the bottom layer.

Many thanks

Russ

Hi, Russ:

You can refer to our application note AN15 for guideline of the EMC and safety rules.

http://www.powerint.com/sites/default/files/product-docs/an15.pdf

Yes, for EMC performance, I will highly encourage you to follow a good basic design rule, you can refer to the related application note depending which IC you are going to use.

Hope this is helpful for you.

Thanks