L6562 : Need to understand the functionality of the PFC IC

[jayanth]

Hello everyone,

I have made the L6562 ref circuit (for 250W provided in the datasheet) on general purpose PCB.

I have discussed with coilcraft members, they have said, for initial conditions the resistor divider from rectified mains input will provide the Vcc to the IC. After IC turns ON, it will switch the inductor and coupled inductor will give the stable voltage to Vcc.

But in my case IC is receiving 12V from rectified mains input, But it is not switching the inductor.

So, IC is not switching, this is why output is not boosting up to 400VDC. It is still at 312VDC.

Thanks and regards,

Jayanth.

[MMore.626]

Hello,

can you post some waveforms (input current, auxiliary voltage before diode, drain voltage of the main mosfet). When the IC starts you can see if turns ratio is correct, if winding phases are correct) etc.

Thanks 

Mauro