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3 leds, 700mA, 7,4W, TRIAC dimming

Posted by: muhombre on Fri, 03/16/2012

Good day!
I need your support in designing led driver for 3 leds, input 220V, output 700mA, 7,4W for switching and TRIAC dimmers.
I examined Design Examples and think that DER-302 (TRIAC Dimmable, Power Factor Corrected, 7.2 W Non-Isolated LED Driver, 185 VAC – 265 VAC Input) is the most suitable for my purpose. But it designed for 200mA leds.
On there is Device Selection Table from which I chose LNK457 (700mA, 3 leds). Could you help me to adoptise DER-302 for my purpose or advise some literature to read.
Thanks beforehand!


Submitted by PI-Crumb on Fri, 03/16/2012

Thanks for using this forum.

DER-327 is 7.5W, Triac-Dimmable LED driver design for a 9V (typical), 800 mA output and optimized for 230V input. This is very similar to your requirements.

It will be released probably by next week in PI website. This will provide you with very good information that will aid you in doing your design. Kindly wait for its release.

Submitted by muhombre on Sat, 03/17/2012

Thank you very much! I will try to realise it.
I'm going to use 3 nichia leds. Maximum current is 800mA. On this current voltage will be about 3,4V for each - the whole voltage 10,2V.
The whole flux will be 690 lm. I hope.


Submitted by gustavjosefsson on Fri, 06/01/2012


I'm looking for a similar reference design for 700mA triac dimmable 230V for at least 7,5W. DER-327 sounded as a very similar design but I cannot find it.

When do you expect it to be released?

Thank you!
Best Regards,

Submitted by PI-Crumb on Mon, 06/04/2012

I'm sorry if DER-327 was not yet released. I made another inquiry and the latest info I got is that it will be posted this week.


I cannot see any posting/publishing of DER-327 yet and its Friday. Will it be posted today?

I have been waiting for a long while for it (since your posing i Mars 16:th). 2,5 months has passed now! :-(

Could you please poke the engineers and make them hurry a little more!? :-)

Best regards

Submitted by PI-Crumb on Fri, 06/08/2012

hi Iman,

I attached the draft copy to get you started. Thanks.