LYTSwitch-3 Inductor Design Spreadsheet

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I have seen that DER-524 8W reference desig using LYT3325D is using a nice to have inductor design spreadsheet like what we are used to in PI Expert. Yet the LYTSwitch-3 series isn't supported in the software. However, you obviously have a spreadsheet already that does at least churn out the right values - especially for dimming curve and RBS2.

We want to use the LYT3328...

Any chance you might share your Beta-version of that spreadsheet with us?

We have produced thousands of drivers for the old LNK306 then moved to the LNK460 which has since been replaced by the LYT4.
But the LYT3 for European (220VAC) is really what we need.

Buck-boost or flyback are all OK.









The software is due for release on April 1st. Please let me know if you still can't access by then.

Here's the link to the online PIXLS version:


Dear PI-Crumb,

Thanks a lot for adding LYT3 support to the online version.

I tried a buck topology using an EE22 core for 30V 500 mA (15W) LED configuration.
In the spread sheet I noticed that there is a suggested value for wire gauge (AWG) of the bias winding - #30 AWG in my case.

My guess was that the primary (between pin 1 and pin 8) would be #36 or #34 AWG. I am right?

We based our reference design on DER-511 - 7 W TRIAC Dimmable, High Efficiency, Power Factor Corrected Non-Isolated Buck LED Driver, but the later is for American AC voltages not European 220 VAC (there is no buck reference design for 220VAC mains).

Many thanks for your patience with this.



hi Rene,

Please double-check the spreadsheet. The AWG30 should be the suggested wire size for the output inductor. There is no wire size recommendation for the bias winding on the spreadsheet, but AWG#34 is acceptable for bias.

Dear PI-Crumb,
Many thanks for your recommendation and excellent support!

Btw. the buck-spreadsheet for the LYT3-Switch will show 'Total number of turns' which might lead to confusion since it is more the No. of turns of the output inductor. Someone might think it is the total No. of all windings in the assembly. :)


Thanks for your feedback. I will forward your comments to the PIExpert group to further improve the description.