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LNK304 Output Voltage drops

Posted by: EmbeddedDesigner on

Hello everyone,

hope someone can help me on this one.

I am using the Power Integrations LNK304DN-TL at 5V output voltage. When the microcontroller is not utilized and unprogrammed (powered at 3V via a LDO), the voltage is stable at 5.0V.
However, if I programm the microcontroller and let it operate (consuming circa 80mA, <120mA as specified in the datasheet), the voltage drops to 4.5V.
Is this normal? Can you give me some details on the voltage swing/tolerance? I would be thankful if you could provide me with a spice model and/or some hints, as to whether this is normal and what should be considered.
I would be willing to share my circuit with a FAE, not publicly as this is a commercial project.

I am waiting for a reply, as we are expecting to start qualification by the end of this month.

Kind regards
J.

Comments

Submitted by PI-DATA on 01/11/2018

Hi,
Output voltage regulation should be within 5%.
To check your component values/design you may want to visit our online design guideline below.
https://piexpertonline.power.com/site/login

Regards.

Submitted by Easy Peasy on 01/13/2018

What is your lowest input voltage? does it have substantial ripple? does the 4.5Vout have substantial ripple? try a bigger link switch, or a cap on the HV to bring up the min valley voltage...

Submitted by PI-DATA on 01/23/2018

Hi,
If you have still problem, please let us know.
Thanks.