LNK305 Power delivery capacity

Posted by: abhishekmoghe.1 on 11/15/2018

Hi ,
I am using LNK305D in one of my project. for universal input, i need 5V 280mA Peak Power and average power of 5V 180mA. i am using direct feedback for LNK305.
datasheet says that device can provide 280mA for universal input range but when while testing we observed 2 cases
case1 : When operated at 110VAC 60Hz
LNK305 turn off at peak load of 240mA when operated at 110VAC 60Hz
Case 2: When operated at 230VAC 50Hz
LNK 305 turn off at peak current of approx 370mA.
And it turns ON -OFF with fixed time interval? what would be the cause of this behavior? Turning off at different current levels?
Is it recommended to use LNK 305 or LNK 306 for 5V 300mA Power level.
I have attached waveform of output voltage and current when device turns off.
appreciate your help ..!

Files

Turn off @ 5V 240mA @ 110VAC 60Hz (116.36 KB)

Turn off @ 5V 360mA @ 230VAC 50Hz (125.25 KB)

Comments

Hi abhishekmoghe.1,

Could you please upload your schematic? thanks!

You said that it turns off and on with fixed time interval, can you also please measure the on and off times?

Thank you!

Regards,
PI - Pike

Hi,
Please find attached schematics and wave forms.
Load is applied at +5V output. Across C11.

Attachment	Size
Document includes schematic and turn ON OFF Waveforms. (131.16 KB)	131.16 KB

Hi abhishekmoghe.1,

Can you check the temperature of the device? I think it hits the thermal shutdown threshold.

Regards,
PI-Pike