KP_TRANSIENT

Posted by: saiknaram on 08/13/2021

I didn't know if the last comment thread is archived or not so I thought of creating another forum topic. Sorry if that post is not archived.

I'm having trouble with the parameter as I am trying to design for output current of 0.36A with the LNK3206D but with a inductor of 470 uF I am above 0.2 KP_TRANSIENT but the inductor value is too small.

So when I increase the size of the inductor to 1200 or 1400uH, the KP_Transient drops to 0.09 which is another violation. I noticed that the design is setup as a MCCM. I am trying to design for CCM.

Would really like to know how I can make this work.

Please see the image attached for more information.

Thanks!

Files

PI-KPTransient.PNG (58.98 KB)

Comments

Adding picture.

Attachment	Size
PI-KPTransient_0.PNG (58.98 KB)	58.98 KB

Hi saiknaram,

Good day!

The post was not archived and your inquiry has been already acknowledged by our representative and will be attended in a while. I am glad that you created a new post. In the future, I encourage you to do the same and simply copy the link of the thread in your new post if you think relevant.

Thank you and regards,

PI-Lupin

Hi saiknaram,

Since this is an on/off controller, the sequence of pulse cannot be periodically CCM or DCM. MCM means 'Mostly Continuous Mode' and implies that a majority of switching pulses will be continuous. With regards to KP_TRANSIENT, the spreadsheet is simply flagging an 'Info' message notifying the user that an SOA trigger may occur and should be tested in the actual prototype. Unlike a 'Warning' message, this is not a catastrophic event/failure.

Thank you.