TPS54360: How to avid burst mode

YUKI YAMAGAMI

Prodigy 50 points

Part Number: TPS54360

Could you tell me how to avoid the burst mode switching?

I use the TPS54360 to get 5V-output from 25~26V-DCinput.

When the output load is light (about 0.5A), the device operates the burst mode switching.

I tried Compensation which written in the datasheet , but I can't stop the burst mode.

Are there any problems in my circuit or condition ?

The condition is below.

Input voltage:25~26V

Output voltage:5V

Output current:0.5~1A

switching frequency:1.6MHz

The circuit is below.

over 6 years ago

0 David Baba over 6 years ago

TI__Mastermind 40040 points

Hello,

Do you have a scope shot of the switch node? Can you please share? Also I was not able to open your schematic?

Sorry I clicked TI think its resolved by accident. I will reopen.

Thanks.

David.

0 JohnTucker over 6 years ago in reply to David Baba

TI__Guru**** 191445 points

Hi User,

The TPS54360 eco-mode boundary is somewhat unpredictable. Please see this app note:

www.ti.com/.../slva388

It is applicable to TPS54360 as well. Let us know if you have further questions.

0 YUKI YAMAGAMI over 6 years ago in reply to JohnTucker

Prodigy 50 points

Hi John Tucker,
Thank you for your repply and introducing me the app note.
I'll check it soon and if this problem is not solved,I will ask something.

Sincerely,

0 YUKI YAMAGAMI over 6 years ago in reply to David Baba

Prodigy 50 points

Hello David Baba,

Thank you for your reply.

I attached circuit picture file in that text window by cut and paste but I can't see.

Next ,I Inserted the schematic file.

Can you see this file?

Thank you,

webench_design_5051250_7.tsc

0 David Baba over 6 years ago in reply to YUKI YAMAGAMI

TI__Mastermind 40040 points

Hello,

The waveforms with the bump on it are normal. It is normal for the Vsw node to ring like this when the inductor current goes to 0A. It looks like there is some interaction between CCM and DCM. I think that as you increase the load, the switch node will be very stable and periodic.

It is typical to have some difficulty on triggering on a scope, the swtich node waveform at the boundary of DCM and CCM

Hope this helps?

0 YUKI YAMAGAMI over 6 years ago in reply to David Baba

Prodigy 50 points

Hello,

Thank you for your help.

Finally,I changed the switching frequency 1.6MHz to 0.8MHz and output inductor L and comp R and C.

Due to these changes, the burst switching stopped and became stable continuous switching.

I appreciate your kindness help and TI support team.

Thanks,

Power management

Power management forum

TPS54360: How to avid burst mode