power supply with LNK306 @ 12V/280mA

The final circuit topology in Table 2 of AN-37 gives the basic setup needed for the circuit you intend to use.  If you haven't already, download out PI Expert software and use PIXLs Designer to create a new LinkSwitch-TN Buck Boost design.  You need to enter your input voltage variables, output voltage, output current, etc and very quickly, the spreadsheet will give you the majority of the information you need to create that reference design. 

-The Traveler

Thank you for reply.

I donwloaded the PIXLs designer and design a low side buck boost with optocoupler using a LNK306. I have another problem.

I need to use a non-isolated power supply with the following characteristics:

input: 85-265Vac

output: 5Vdc-600mA

I designed a power supply with 12Vdc-250mA using the LNK306, but to get the 5Vdc-600mA, I need DC/DC converter beacause of the drop-out voltage.

Is it possible to design with a non-isolated power supply with 5Vdc-600mA output with a LNK or other components from powerint?

Thank you 

With the non-isolated design, are you trying to avoid using a transformer all together? 

-The Traveler

Yes,

I don't want to use transformer in my design. 

I I try to optimize the current consumption on my board, does a Low side Buck Boost with optocoupler converter is acceptable in term of power with the following characteristics:

Input 85-265Vac / 50Hz

Output: 6Vdc - 0.32mA continuous

Does the LNK306 can give continous 320mA  output current?

Thanks 

For the higher output power, you could use one of our LinkSwitch-CV parts. However, the feedback pin operates differently than on the LinkSwitch-TN parts. With LinkSwitch-TN, the current flowing into the FB pin determines whether or not the part skips or switches each cycle.  In LinkSwitch-CV, the IC is sampling the FB pin voltage, which is referenced to SRC.  You could sample the output voltage directly through a resister divider with LinkSwitch-CV but the output of the power supply would need to be referenced to the SRC connection making the topologies shown in the LinkSwitch-TN datasheet impractical.  

If you just don't want to deal with safety isolation and are ok with using a small transformer, you could use LinkSwitch-CV with a very simple winding arrangement for the transformer.

Another option would be to use two LinkSwitch-TN devices in parallel.

Regards,

The Traveler