AC/DC converter having power saving under 100mW

Sep 01, 2008 11 Replies

Hi all,



I would like to built an AC/DC converter with universal input (90~264Vac) and one 12V/2A output.



It need to having power saving under 100mW when the output loading is



40mW.

Can anypne suggest me PWM ICs which can acchieve this target...



Thansk!


Webber.


"webber"

** That is a ridiculous requirement.

** What ever for ?

..... Phil

I think the EPA Energy Star (tm) requirement for a nameplate 24W power supply is more like

Best regards, Spehro Pefhany

"it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

"Spehro Pefhany" "Phil Allison"

There might be something here, but I haven't looked at their stuff for some time

formatting link

martin

It can be done with a uC. 40mW @12V is 3.3mA, good enough to run a uC monitor to switch off the main SMPS. But you would need a secondary (self controlled?) SMPS to run the micro.

Another method might be to charge a capacitor and run the uC from that. Power up the SMPS for a short period to recharge. And repeat.

Feasable?

That's the trick. Essentially you almost need to build a second micro switcher that takes over once the load drops to minimums. How fast the big one will be able to come on line when the load surges up again is a whole 'nother matter and that is not trivial at all.

Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.

Or in SMPS speak, burp mode? Shouold be feasible but you'd need a post-regulator. The challenge will always be what will happen when the load comes back with gusto.

Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.

The only approach that might work, is a fleapower converter (like,

12V/100 mA) that has high efficiency at low current, and a second converter (12V/2A) that is disabled unless the current drain requires it. DC/DC converters intended to be paralleled have a suitable interface that you can copy (basically, all the sense amplifiers have external coupling to ensure load sharing).

Hmmm. can you even do a bridge rectifier under 40 mW?

Done it many times. Use small diodes, not them big leaky ones :-)

Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required