PFS at 400 HZ
I have a design based on rdr236.pdf and rdr239.pdf. The PFS section is working but we are using it 400 HZ. The ripple current on the input AC is over our conducted EMI limit by about 10 db at 1/2 load. What can I do to reduce the ripple?
i am including waveforms at 60 HZ and 400 HZ 115VAC input current. Full load 200W output and 1/2 load 100W output.
The PFS is switching at about 25 KHZ at 1/2 and full load. I believe it should change from about 55 khz to 70 khz per the data sheet and PIXIS designer data..
You have all the design data in another post PFS and LCS Power Supply.
Comments
Since the 25KHZ is not a sine wave there are harmonics and our requirements start at 150 khz.
more attachments.
I figured it out . The part should be a 712 but is a 716.
"...over our conducted EMI limit by about 10 db at 1/2 load"
"The PFS is switching at about 25 KHZ at 1/2 and full load."
1) You have a conducted EMI spec at 25 kHz?
2) Can you capture the choke current waveforms at the same conditions as the scope shots you attached?