TPS56A37: PG terminal output of the TPS56A37

?? ??

Part Number: TPS56A37

Tool/software:

When the PG terminal of the TPS56A37 rises, it shows the following waveform.
Is it possible that the IC is the cause of the waveform shown below?
(CH2: PGOOD, CH3: +5V)

The circuit diagram is as follows, with PG terminal connected to the EN terminal of the TPSM82903SISR.

6 months ago

0 Calan Elaya 6 months ago

TI__Genius 11175 points

Hello,

Can you share waveforms of PG, Vin, Vout, and SW together when the issue occurs? This will help me understand the issue better.

Additionally, I would recommend 100kohm resistor tied from PG to VCC. Can you try this and let me know the result?

Thank you,

Calan

0 ?? ?? 6 months ago in reply to Calan Elaya

Prodigy 10 points

The waveforms of PG, Vin, Vout, and SW are as follows.

Also, There is a 100kΩ resistor tied from PG to VCC (5V), but does this mean that it needs to be connected to a different voltage?

0 Tahar Allag 6 months ago in reply to ?? ??

TI__Mastermind 32350 points

connecting PG to 1o VCC thru 100K resistor should be OK.

here is how the plot should look like. can you probe VCC to see if it collapses with it.

0 ?? ?? 6 months ago in reply to Tahar Allag

Prodigy 10 points

Since Vcc = Vout (5V), as shown in the waveform above, Vcc is not collapse with it.

0 Calan Elaya 6 months ago in reply to ?? ??

TI__Genius 11175 points

Hello,

I see you also have PGOOD connected to the EN of another device. Can you remove the connection to the TPSM82903SISR, leaving only the 5V on the PG of TPS56A37. Please provide the waveform after this is done to view the result.

Thank you,

Calan

0 ?? ?? 6 months ago in reply to Calan Elaya

Prodigy 10 points

When I removed the connection to the TPSM82903SISR the PG waveform improved.

0 Calan Elaya 6 months ago in reply to ?? ??

TI__Genius 11175 points

Hello,

I am glad to see this resolved the issue. Looks like the TPSM82903SISR was causing a slight glitch in the PG waveform when it's enabled. Does this help resolve your issue? If any further questions please let me know.

If this solves your issue please don't forget to click "This resolved my issue", and I can close this thread.

Thank you,

Calan

+1 ?? ?? 6 months ago in reply to Calan Elaya

Prodigy 10 points

Thank you.
I understand that the TPSM82903SISR is the cause.
But why does the waveform look like this when the PG terminal is connected to the EN terminal of the TPSM82903SISR?

0 Calan Elaya 6 months ago in reply to ?? ??

TI__Genius 11175 points

Hello,

The 5V PG of TPS56A37 is Enabling the TPSM82903SISR. When the TPSM82903SISR is enabled and begins to ramp up, it is causing a minor glitch in the PG waveform of TPS56A37. It does not significantly disturb performance, but simply causes a minor glitch in the startup waveform of PG in TPS56A37.

Hope this helps. If any further questions please let me know.

Best,

Calan

0 ?? ?? 6 months ago in reply to Calan Elaya

Prodigy 10 points

thank you. This resolve my issue.

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TPS56A37: PG terminal output of the TPS56A37