LNK564DG 12vdc output
Hello PI,
I have built for a few days the LNK564 6v 330ma CV/CC Power supply.
And it works very nice.
Know i got the 12v Transformer from Wuerth (750 871 032)
And i would like to upgrade the schematics to a 12v supply. But i do not truly understand the R1/R2 Resistor Network. How can i calculate the network ?
It is important to hold the FB Pin on 0.8 v ? so if i insert a Poti and change the voltage on the fb pin to 0.8v ? or are there some other forms to calculate it ?
Or is out there an example schematic for a 12v version ? that would be very nice. I use this supply for an Atmel Board and need the 12v for an rail to rail opv. for a 0-10v output.
thank's a lot for your inputs.
best regards
Michael
评论
Hy PI_Crusher,
thank's for the reply and links.
I will test it in my lab.
Cheers,
Michael
Hello Michael,
See http://www.powerint.com/sites/default/files/product-docs/an39.pdf page 13 for 12V output and R1 and R2 values, use transformer B from page 15 (note you have to add 4 turns to the secondary winding). Read throughout this document, you will find useful information. FB pin voltage is a feedback voltage; you do not artificially change that. With 12V output and recommended R1 and R2 values you will read 0.8V on FB pin (an internal reference + comparator keeps this FB voltage at 0.8V during steady-state conditions, see page 2).
See http://www.powerint.com/en/design-support/reference-designs/design-examples for examples (like http://www.powerint.com/sites/default/files/PDFFiles/di178.pdf).
Cheers,
PI_Crusher