1. How to set switching frequency(Fsw) of InnoSwitch3-Pro?
The data sheet shows of InnoSwitch3-Pro that designer can set the switching frequency(Fsw) from 25kHz to 95kHz in page 34 of 50. But how to set, by hardware setting or it is Programmable? I've browsing relative documents including datasheet, application notes, design example, but haven't found what's the specific way to set Fsw.
2. How to manipulate Output voltage and current, by hardware setting or it is Programmable?
As the attached file, I uploaded my design suggested by PI Expert.
3. Why Choose 68.3Vdc for primary side of transformer?
The Np/Ns suggest by PI Expert is 41:3 which means the Value of Voltage in primary side is 5Vx (41/3) = 68.3Vdc
My experience in transformer is simple in the past. I used to design fixed input(110VAC or 220VAC) rather than universal input(85~264VAC). Which means the Voltage of primary side is fixed. as opposed to using InnoSwitch3-Pro, I have to determine the voltage of primary side first. That makes me difficult due to I don't know exactly how to choose the value of voltage in primary side and why. Really needs help to proceed forward development with InnoSwitch3-Pro.
Thanks in Advance!