Forum Post: UCC28950 / abnormal gate function

Hi,

I’d like to ask about the function of UCC28950.

My customer evaluates load transient on his DCDC converter board, but he found some abnormal function.

He confirmed that outC/D lock up for 1 cycle after load transient(500mA→50A) regardless of outA /B waveform is normal, and he said this causes bias magnetism of transformer.

-----------------------------

-CH1:outC

-CH2:outD

-CH3:current flowing through the primary winding of power transformer

-CH4:pulse transformer(primary side)

-----------------------------

Is it probable function that outC/D lock up regardless of outA/B waveform is normal?

I think outC/D is associated with outA/B, and outC/D doesn’t lock up independently.

Could you advise me please?

I’m sorry that I can’t get schematic of the board(it is my customer’s matter).

The condition of DCDC converter board is Vin=270-280V, Vout=28V/50A.