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Power Integrations Engineer Power Integrations ModeratorPFC inductance calc for Hyper_PFS and mounting question
When using PI design software for a PFC w/ the Hyper PFS part:
If I choose a Sendust core, the LPFC_0-bias > the LPFC but if I choose Ferrite, they are equal. Please explain. Why is the LPFC value greater for a ferrite core than for Powder Iron or Sendust?
Also, 2nd question: It appears that these Hyper_PFS parts are designed to only be used with a vetical pcb mounted heatsink. Is there any plan for a differnt package or lead form for attaching the part to a mounting plate that is parallel to the pcb?
cjf3
The permiability of amorphous cores changes significantly as the H field changes --> that's why the inductance changes with current. That's why the L0bias is different in sendust cores. since this does not happen with Ferrite cores you don't see this phenomenon.
About vertical mounting - You should post this in the Hi Power forum - I'm not sure what the correct answer to this is...
PI-Spock | 695 posts I understand that the zero bias L can be higher w/ Sendust or even Powder Iron, but why is the inductance at rated current different?
cjf3 | 9 posts That's because the the H field is a function of current flowing through the inductor. As the current increases the H field increases thereby the permiability, and inductance drops in value
PI-Spock | 695 posts If the design software gives a zero bias L of 1mH and full load L of 300uH for Sendust but gives an no changing L of 500uH for Ferrite, why can't the Ferrite inductor be 300uH like w/ the Sendust?
cjf3 | 9 posts It can be. Just change the KP value at the top of the spreadsheet if you want to control the value of inductance (at full load)
PI-Spock | 695 posts 