L4985

[kmpandav]

In my 750W PFC project, I've employed the L4985A PFC controller IC. I utilized the e-design suite offered by ST to design my PFC, and I fabricated the PCB using the components specified in the e-design file. Despite ensuring that all the necessary voltages at respective pins are within their recommended ranges (as per the datasheet), I am encountering PWM pulses at Pin 2 of this IC.

Could you please help to resolve my issue.

[AScha.3]

>PWM pulses at Pin 2

this is the gate drive ...it should make pulses.

whats wrong then ?

[kmpandav]

I am not getting any PWM pulse at pin 2 to drive MOSFET of boost converter in PFC.

I cross verify all the components and check voltage at each pin of L4985, the value I got at respective pin are within their recommended range mentioned in the datasheet.

[AScha.3]

you connected to mains ?

old school tip:

to avoid big explosions  🙂

use a 60W or 100W lamp , in series to mains hot phase ;

this allows to have mains voltage at your circuit, but in case of something wrong, short or mosfet dead,

just the lamp gets bright...then you know: too much current on the circuit...

and for beginning, only a light load ; maybe two 25W lamps in series, about 10W load then.

for safety and easy testing with a scope, use a mains isolation transformer;

so ->  mains -> transformer -> 100W lamp -> your pfc . -> "gnd" return to transformer.