PFS7323H & PFS7324H?

Hi,

we do not have PFS7323 and PFS7324 in H package from HiperPFS-II family.

But We do have PFS7523 and PFS7524 in H package from HiperPFS-III family.

I would strongly recommend to use HiperPFS-III family devices for any new design.

You can find product information for HiperPFS-III at following location

http://ac-dc.power.com/products/hiper-family/hiperpfs-3/

May I know what is the anual estimated quantity for this design?

Regards

PI-NANO

1000+. Currently commited to 300 by Dec. I haven't found current stock of PFS7524H. What is the availability?

Since I can't find stock, I have to keep pushing on the hiperpfs-2. Our line frequency is 360-800 Hz and I am getting some instability in the input current  around 400Hz. It looks like it is misinterpretting the zero crossing because there is a glitch in the input current preceeding it.

I am also confused on the calcuation for R7 (from PI expert). The design reports 10.2k, but calculations from the datasheet give me a value of 3.23k.

What will I have to alter for operation at our increased line frequency? What is the correct value for R7 based on 385VDC out, 105-110 watts, and 120uF output capacitance?

Adding screen captures of input current.

PFS2 was not designed to work with 360-800 line frequency. May I ask why this project needs such high line freq since typical is 40~80Hz.

Could you share how you calculate the R7 to be 3.23k? Also a spreasheet will be helpful. 

I design for aircraft power. Typical is 400Hz, but can vary from 360 to 800. I did see a post from another user asking about this frequency range and the response that they are not designed for these frequencies.

I did have an error my calculation, but the datasheet for PFS2 gives the following equation R7 (kOhms) = Rz = Pmax / (1.2 * Vout^2 * Cout)

110W / (1.2 * 385V^2 * 120uF) = 5.15k

PI Expert has R7 = 10.2k, the datasheet recommends 7.5k.

I also found that the output voltage is 392V using the given values for R1 - R4 (1.5M, 787k, 1.6M, and 60.4k respectively). PI Expert gives a warning about the output voltage being too high when I specify 392V.

I am currently using 1.54M for R3 and the output voltage (when the input current waveform is stable) is 386V.

I uploaded the output of PI Expert and the datasheet I have been using.

7.5k is proven works proper on bench. So you could use 7.5k.

the Feedback resistor has to be 1% for accurate regulation. It is OK to fine tune the feedback resistor chain until you get the Vo as you want. Note the temperature variation and resistor tolerance can be evaluated if you have a production design.