this PFC circuit my input is ac from 200 to 240 Vac and TB1 is the input to the circuit after full bridge rectifier(there is full bridge outside this circuit)
C1 is actually .3uf and C2 is 450uf , I have problem with this circuit with load regulation , it works fine up to 500 W and after that when I increase the load the output drop a lot(from 400 to 320 Vdc) ,and if you look to the scope you see the pule width is not increasing when the load increase to regulate itself , so my question is why the pulse width is not increasing when the load increase?
and notice also that I sence is less than .2v at this case.
CH1 gate pulse, CH2 VDS, CH3 is the chocke current.
View attachment 92206 from 200-240 vac

 

it works fine up to 500 W and after that when I increase the load the output drop a lot(from 400 to 320 Vdc) ,and if you look to the scope you see the pule width is not increasing when the load increase to regulate itself , so my question is why the pulse width is not increasing when the load increase?

It's easy to realize you're exceeding dynamic range IWHT that's obvious! Now I ask is this serious question or just quizzing us??

 

It's easy to realize you're exceeding dynamic range IWHT that's obvious! Now I ask is this serious question or just quizzing us??

how do you fix that, what do you mean by IWHT, sorry may be my question is stupid bur really I do not know

 

how can I fix this problem