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Buck boost led driver

Posted by: passad on

Hi, I need a design for a led driver with 28W @ 350 mA, 82V output but it should be adaptable to provide from 24W to 33W. It seems to me that the Buck-Boost topology with an LNK409EG or LNK419EG is the most simple and economical. I've tried the PIXls Designer (Release 8.6.0.2) but for the LinkSwitch-PH the only option is the Buck topology. Could you please help me with a design spreadsheet, schematic, etc..?

Thanks in advance and best regards!

Paulo

评论

Submitted by PI-Crumb on 06/10/2012

In the PIXls designer, please choose "LinkSwitch-PH" option. This is by default based on flyback topology, but if you want to use it as buck-boost, please set VOR = VO.
For additional info, please check DER285 as well which I found to be close to your requirements, if you wish to use buck-boost.

Thanks for your comments. In the DER-285 I think I should ignore the Transform Secondary Design Parameters section, right?

In DER-285 schematic diagram: wich resistors correspond to RV1, RV2, FB pin resistor Upper V pin resistor and LowerV pin resistor? (Just for the sake of not misreading!)

Regards,

Paulo

Submitted by PI-Crumb on 06/18/2012

Please ignore the transformer secondary design parameters.

RV1 is the upper Vpin resistor, which corresponds to R3 (2Meg) and R4 (2Meg) on DER-285. There is no RV2 on the design.

For FB pin current, please refer to DER-285 p.11 (Circuit Description)

Submitted by passad on 06/18/2012

OK! Thanks a lot!!!