AC/AC External Power Supply and EUP

The EUP directive says "no load condition" must not exceed 0.5W.

Do you mean 0.5W power dissipation? If so what sized power supply? AC/AC sounds like a transformer to me and so the 0.5W would likely be core losses, but again what sized transformers?

I am guessing this relates to Energy using Products (EuP) Directive (2005/32/EC), but I am not sure which study (Lot number) you are talking about

http://www.mtprog.com/cms/eup/

Can you site the specific details of the EUP directive including the full text and what products it is meant to relate to please. A little more information would be helpful.

Standby and off-mode losses of EuPs, Lot 6
Or more precisely Commission Regulation (EC) No 1275/2008
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:339:0045:0052:en:PDF

And
Commission Regulation (EC) No 278/2009
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2009:093:0003:0010:EN:PDF

'no-load condition' means the condition in which the input of an external power supply is connected to the mains power source, but the output is not connected to any primary load;

Not talking about a specific PSU just AC/AC PSU in general.

External power supply: it is designed to convert alternating current (AC) power input from the mains power source input into lower voltage direct current (DC) or AC output;

Most AC/DC PSU's seem to be EUP compliant now, but AC/AC PSU's dont.

Hope this is enough information

I am still a little confused by what type of AC/AC power supply you are discussing. A standard AC/AC power supply would be a transformer, in which case the transformer would need to be a low-loss type to minimise transformer core losses (and hence comply with the off line power dissipation limits of the standard). For small mass-produced (cheap) transformers your core losses are going to be high.

What size transformer and load are you talking about? Are you talking about a transformer or some sort of switch-mode AC/AC converter or low power voltage divider network?

Can you please provide more information on your AC/AC power supply and application.

Hello for AC/AC supplies it is indeed difficult to overcome the legal requirements.

In consumer electronics since some time solutions were implemented where a small switchmode power supply (which can cover the directive) manages a microcontroller controlled power supply relais and only in operation the full power AC/AC supply is attached to the grid. This solution can be designed to fullfll the legal requirements in case of AC/AC power supplies too. For instance the MCU just understands the remote commands needed to turn on the TV - the full control was then done via another MCU.

Sufficient small powersupplies can be designed based on ST Viper or Infineon ICE ICs and system solutions which including the MCU and relay can meet stby power of 200mW or even better

Best reards

Is it not possible to integrate a relay (switch) between the AC/AC converter and the main supply?

When the AC/AC converter is in no load, it is not connected with the main supply.

In this case only the supply system for the relay will be connected continuously to the main supply.

Sounds like politicians tried their hand at engineering again (and failed as usual.) if you ask me.

Rules? We don't NEED no stinkin rules! =b

To give a fix limit on losses without limit on the PSU size doesn't make sense. 0.5W of losses is reasonable for a 10W PSU but that's it.

My standard 250KW ozone generator PSU consumes ~1K to stay "alive" in standby mode. This is less than 1/2% of losses but 2000X the limit you are mentioning.

There is a limit of 250W. Higher than this and it is exempt from EUP.