lnk586 startup issues
Hello,
I'm trying to design a low power standby AC/DC converter using the LNK586, however I cannot get the part to work. I am using the evaluation board for the LNK616PG converter with a few mods to match the example schematic for the LNK586, but it still is not working. One issue that I've observed is that the voltage on the BP pin is <1V, even though it is supposed to be >5V.
I've tried calling a number of sources trying to get design support with no one returning my calls. I really need some help!
Thanks.
Comments
Is there anywhere I can purchase the development kit shown? I can't find any kits for the linkzero family. I think that would help me more than anything.
I modified the evaluation kit of the lnk616 to match the example schematic shown for the 584 exactly, but it still doesn't work. My concern is that the transformer is just too different. Although even when I connect the board to the AC supply, the part doesn't even start switching. The Bias pin goes to 1.1V and it just stays there. Even if I short the bias pin to ground (through a 100 ohm resistor), it doesn't do anythiing once I release the pulse. There's nothinig dragging the bias pin down, so I don't understand why it doesn't go to the 5.8V its supposed to.
The part has a power down mode which is probably getting triggered.
Its a bad idea to use the LNK616 platform to operate a LNK586 in...
There is no RD board for this family... I'll check to see if there are other designs I can refer you to and send you a message.
Ben -
As we don't have a publicly available Reference Design for this part just yet, I would suggest using the DER-260 report to spin a quick proto-pcb in house. You *might* be able to modify the LNK616 board but the layout will likely be far less than ideal and will probably cause more problems than the trouble it's worth. The problems you're experiencing currentlly are a good example of why you don't want to use the LNK616 PCB. It's not as straight forward of a modication as you initially thought.
Using the DER-260 as a starting point, you can modify the PIXLS design for use with a LNK586 very easily and can even use the same transformer (regapped for a different inductance) if you keep the same output voltage. You'll need to change a few other components on the PCB but the changes should be minimal.
If you don't want to go to the trouble of laying out a new PCB, the gerber files are available for download on our website. You should be able to give these directly to your PCB vendor and have them create some prototype PCBs that you can work with. The rest of the BOM is available in the DER-260 report and has all the manufacturer part numbers. The vast majority of the items should be readily available through Digikey and/or Mouser.There is even a complete diagram with instructions on how to wind the transformer for DER-260. If you don't have the means to create prototype transformers in-house, we ofter a transformer prototyping service which can be found on our design support page.
-The Traveler
Please attach your specification... Input voltages, output voltages, power level, etc etc
LNK586 is a different family from the LNK616 and the eval platforms may not be compatiable.
Look at the following report to get started on the LNK58X family...
http://www.powerint.com/sites/default/files/PDFFiles/der260.pdf
This report uses the LNK584 but the LNK586 is scalable to this particular platform. Send me your spec first so that I can take a look.