Hello, when I was seaching for infos on how to use a standard Computer in a truck or bus, I came across the "active PFC" and read, that I should use it in DC/DC converters to, to avoid the high switching frequencies on the bordnet. Can someone tell me, which PFC chip I should use for it and maybe some links to application notes and schematics? Thanks Kayham
I think that makes no sense. PFC means power factor correction, and for a power factor you need alternating current. But in a 24V net, you have DC current. To reduce high switching currents, you just need a good filtering, so input capacitors and inductors must be well chosen. Regards, Martin Antoni
This is one of the source where I found the thing with the DC PFC: http://www.smps.us/power-supply.html The PFC is AFTER the rectifier, hence on the DC side. Can someone enlight me please? Thanks
> I think that makes no sense. PFC means power factor correction, > and for power factor you need alternating current. He is right.
After the rectifier, you have also a alternating current, but only with positive sign. And then, the current is drawn sinusodial, to match it with the input voltage. This current is then stored in a 'big' capacitor, which is in input to the next switching converter. In this picture, you see the current, which matches in average a sinus http://cr4.globalspec.com/PostImages/200911/PFC_current_waveform_18F5EAD9-CA6B-5E4E-250950656C4D83E6.JPG
Ah OK, makes sense. Greetings Kayham