TPS65218: DCDC4 can't start up when 5.37V<Vsys<5.5V

Sherry Huo

Part Number: TPS65218
Other Parts Discussed in Thread: AM3356

Vsys set up is 5V, When 5V<Vsys<5.37V ,TPS65218 can start up and work normal, when 5.37V<Vsys<5.5V, DCDC6,DCDC5,LDO1,DCDC3 Power-Up Sequence start up ok, when come to DCDC4,can't start up,then the TPS65218 restart. if reduce the Vsys to 5V online, the TPS65218 can start up and work normal. if increase Vsys to 5.4V after start up, TPS65218 can work normal.

Vsys=5.4V,start up, green is Pin13(L4A),purpleis is Pin17(DCDC4)TPS65218_DEBUG_SCH.pdf

over 8 years ago

0 Paul Kundmueller over 8 years ago

TI__Intellectual 1990 points

Hi Sherry,

Thanks for the post! Interesting. Let me take a look at the schematic you provided. I will get back to you soon with an answer. Thanks!

Regards,

Paul Kundmueller

0 Paul Kundmueller over 8 years ago in reply to Paul Kundmueller

TI__Intellectual 1990 points

Hi Sherry,

Would you be able to provide your full schematic and layout? I will send you a friendship request so that we can privately and securely share your design files. Please let me know if you have any questions. Thanks!

Regards,

Paul Kundmueller

0 Sherry Huo9 over 8 years ago in reply to Paul Kundmueller

Prodigy 10 points

customer just give schematic and layout about TPS65218.7851.TPS65218_DEBUG_SCH.pdf PCB Layout of TPS65218.pdf

0 Jayanth Kruttiventi over 8 years ago in reply to Sherry Huo9

TI__Intellectual 1360 points

Thank you for your post. We will review the schematic and update you.

Jay

0 roberto.perez over 8 years ago in reply to Jayanth Kruttiventi

Prodigy 185 points

Hi everyone,
I have the same problem. We are powering an AM3356 with TPS65218 and we hadn't detected the problem right now because we were powering the board with an external programmable power supply set to 5 Volt. But by mistake we tried to power up with 5.03V and at least the DCDC4 didn't start. There is no problem with input voltage below 5V.
We have also try to start up with 5V and after that increase the input voltage. We have reached 5.4V without problem, so we have concluded that there is a problem in the startup. This could be a serious issue just because the previous stage of the power supply may or may not be below 5V.

Any help is appreciated.

Thanks

0 Paul Kundmueller over 8 years ago in reply to roberto.perez

TI__Intellectual 1990 points

Hi Roberto,

Thanks for the post. Would you be able to provide your schematic and layout? If you are not able to provide it on this forum, I can open up a private conversation for you to share your schematic and layout securely. Let me know what you think. Thanks!

Regards,

Paul Kundmueller

0 roberto.perez over 8 years ago in reply to Paul Kundmueller

Prodigy 185 points

Hi Paul,
Could you please open the private conversation?

Thanks

0 Paul Kundmueller over 8 years ago in reply to roberto.perez

TI__Intellectual 1990 points

Hi Roberto,

Sure thing. I have opened up the private conversation. Please accept my friend request then we can privately share your design files.

Regards,

Paul Kundmueller

0 Paul Kundmueller over 8 years ago in reply to Paul Kundmueller

TI__Intellectual 1990 points

Hi Roberto,

I have sent you a private message. To view your messages, please find the messages icon at the top right of your board (see below for an example). Let me know if there are any questions. Thanks!

Regards,

Paul Kundmueller

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TPS65218: DCDC4 can't start up when 5.37V<Vsys<5.5V