Fuse blowing occasionally for LNK305 based AC240V to DC5V/3V

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Hi,

I want to inquire about the Fuse and Transient voltage suppression.
The schematic of the power supply is attached.
generally the supply works fine, but occasionally the fuse blows.

C55 is there for EMI suppression.

Any idea ? or some guideline why the fuse is blowing?

첨부 파일Size
powersupply.png109.33 KB

Hi,

Measure inrush current at highest AC input voltage for this design by turning on the power supply at 90 Deg AC line angle. Take a look at I^2t rating of the fuse.

Fuse selection should be such that it should withstand line surges.

Generally slow fuses will have higher I^2t rating for a given current rating.

Regards,
PI-NANO