Posted on March 28, 2016 at 07:43Hello!
I want to ask a question about chip PFC L4984D.
1. Calculate the inductor according to datasheet. When the input voltage is greater than 200 volts, the inductor begins to make noise, heavily distorted input current. By reducing the inductance, the noise becomes slightly less, but the PFC works in regime intermittent currents. The ideal characteristics are observed only when the minimum input voltage of 85 volts. What material should be used for PFC inductor? Tried X-Flux, High Flux, Kool mu. With Kool mu only managed to achieve more than acceptable results.
What could be the problem?
2. So it is unclear the frequency with which transformation occurs.
According to Datasheet the chip operates with a fixed frequency (FOT). Set the capacitor for a frequency of 70 kHz, but the frequency does not match (is less than a set, and changes during the half cycle of the sine wave of the inductor current).
Regards
#l4984d #pfc #ac/dc
