TPS54202H: TPS54202H

mark salerno

Part Number: TPS54202H
Other Parts Discussed in Thread: TPS54202, TPS54302, TPSM84205

TPS54202 failing @12v input +5 volt at 1 amp output connected to a raspberry pi.

I have designed a board using the application note and the regulator works as expected when first powered up.

I tested the regulator 24 volt input at .5 amp and 1 amp and 1.5 amps with no problems for a 1/2 hour no problems found.

Two regulators have been connected to 24vdc input 1 amp output for 3 days and two of the regulators output went to zero.

The regulator is running cool enough to put my finger on it without burning my skin. ( I am taking temperature readings now)

Replacing the regulator allows the +5 to come back. What can I do to fix the regulator burning out.

Can you suggest on how to trouble shoot this problem.

Thanks

over 6 years ago

0 mark salerno over 6 years ago

Prodigy 110 points

Replaced Part, worked for 10 min .5amps 24volt input (from regulated supply) 45C temp reading, Chip Blew up and smoked when power was reapplied.

0 mark salerno over 6 years ago in reply to mark salerno

Prodigy 110 points

This is our PCB board layout, and attached on another reply is the circuit schematic. Thanks in advance!

400350(A1)Single.pdf

0 mark salerno over 6 years ago in reply to mark salerno

Prodigy 110 points

891350(A1).pdf

0 Anthony Lang over 6 years ago in reply to mark salerno

TI__Expert 4875 points

Hi Mark,

Just want to clarify here, is the damage repeatable on 12Vin or 24Vin or both? Is there any special for the raspberry pi loading? For the layout, I think it is not optimized yet. To minimize the voltage stress on VIn pin, it is better to place input cap as close as possible to IC to make the input and GND loop as short and direct as possible. You could check on the EVM design online.

0 Former Member over 6 years ago in reply to mark salerno

Hi Mark,

From your schematic , the EN pin may suffer 24V voltage which is very dangerous. You can add a RES to divide the voltage to an applicable voltage.

Thanks.

0 Anthony Lang over 6 years ago in reply to Former Member

TI__Expert 4875 points

Hi Bruce,

Good point. The max rating for EN is only 7V.

Hi Mark,

Could you double check on it?

0 mark salerno over 6 years ago in reply to Anthony Lang

Prodigy 110 points

Hello Anthony

The damage is repeatable on both the 12 and 24 volt input. The loading in the raspberry pi as measured is running 500ma to 750ma.

The dabage seems to be on boot up. I will adjust the pcb to move the input cap.

In the mean time I have purchased samples of the TPSM84205EAB (premade boards).

I will put them in the device and test to see if I get the same problem.

Thanks

Mark

0 Anthony Lang over 6 years ago in reply to mark salerno

TI__Expert 4875 points

Hi Mark,

Thanks for bring out new information for us. If the boot cap is the damage point, maybe the root cause is not from layout and potential EOS damage. Could you let us know what type of boot cap you are using, including value, voltage raring, size? Thanks!

Meanwhile, you could also check the point where Bruce pointed out. EN could not endure high voltage on this device.

0 Former Member over 6 years ago in reply to mark salerno

Hi Mark,

As Anthony said, first you can just remove the R3(510k) to float the EN pin , and then check if the damage still remains.

Best Regards,
Bruce

0 mark salerno over 6 years ago in reply to Former Member

Prodigy 110 points

The regulator output will stop because of the internal pull up. So how will that help.
When I first turn on the regulator it works ok.

0 mark salerno over 6 years ago in reply to mark salerno

Prodigy 110 points

Hello all this is the inductor I am using ASPI-0630LR-150M-T15 . It is rated for 5 amps but has a dc resistance of .110 ohms. The evaluation board has a much larger inductor with only .036 ohms. Could that be my problem?

0 Former Member over 6 years ago in reply to mark salerno

Hi Mark,

Float the EN pin to enable, not disable. And what do you mean by "first turn on the regulator it works ok"? Do you mean that when you turn on the regulator another time it fails (float EN)?

0 Anthony Lang over 6 years ago in reply to mark salerno

TI__Expert 4875 points

Hi Mark,

What do you mean about the" because of the internal pull up"? could you give us an detailed explanation? I don't think inductor would be the problem here.

0 Jason Wang (BSR-MV) over 6 years ago in reply to mark salerno

TI__Genius 9550 points

hi Mark, I’m going to close the thread due to inactivity, but please post back if you have further questions.

0 mark salerno over 6 years ago in reply to Jason Wang (BSR-MV)

Prodigy 110 points

Hello All
I traced the problem down to a large voltage spike on the input while disconnecting and then reconnecting the power inuput with a DC jack. The problem occurred intermittently and on several 24 volt to 5 volt converters (not just the TPS54202) It also happened on a TPSM84205 pre made module. The resolution of the problem was to add a protection diode on the input power SMBJ24A 24V 600W SMB Unidirectional ESD diode mouser number 512-SMBJ24A. I also switched from the TPS54202 to the TPS54302. I have built 100 and did not have one fail.

Thaks for your help

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TPS54202H: TPS54202H