The on-time of the MOSFET - LNK3204D

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During the simulation in PI Expert online tool with the LNK3204 as buck converter, I got a warning like
"the on-time of the MOSFET at the maximum line voltage is less than that specified for the device, pick a larger inductor"
I simulated with an inductor value of 680uH, for Vin 217-253VAC

Could you please tell me how critical this warning is. Is it really necessary to increase to a higher inductor value because 680uH is as stated in the datasheet
also applicable as absolute minimum.

I case the 680uH would still be used in a design, what are then the risks, issues that can occur because of this warning?
So please, help me to advise how critical we shall see this warning.

Updating to larger inductor is MUST DO or COULD DO?

Attached the simulation file


첨부 파일Size
LinkSwitch-TN2_Buck.pdf106.56 KB

Hi KarelVanHaver,
Based on computation, the controller cannot deliver you're desired output since it's limited to its Ton. It would be best to increase this to lessen Ton.
You could verify in your actual working unit when you used 680uH the switching waveform if Ton is already at maximum.