TPS65987D: overcurrent protection

K.Yaita

Part Number: TPS65987D

Hi Team,

I would like to ask about OCP (overcurrent protection) of TPS65987D.
My customer set Source Capability as the following with TPS65987EVM that is configured as DFP.
When connected to one PD Sink, he confirmed 20V/1A contract is achieved.
Then he increased the load current at VBUS (20V) on purpose, the cutoff (FET open) occurs around 1.2A.
Is it a normal function of TPS65987D?

I expected the cutoff occurs around 2A because Peak Current is 200%.

Best Regards,
Yaita

over 4 years ago

0 pdjuandi over 4 years ago

TI__Mastermind 29755 points

Yaita-san,

What's the active contract RDO operating current? Can you take the snapshot of the debug registers?

Regards,

Peter

0 K.Yaita over 4 years ago in reply to pdjuandi

Guru 29720 points

Hi Peter-san,

Thank you for your kind support.
I attached the snapshot as the following.

Best Regards,
Yaita

0 pdjuandi over 4 years ago in reply to K.Yaita

TI__Mastermind 29755 points

Yaita-san,

The ILIM should be higher than that around 2A, I think this configuration is not loaded correctly to the flash.

Can you re-flash and I'd suggest this time maybe use tool like dediprog or Aardvark to program the flash.

Regards,

Peter

0 K.Yaita over 4 years ago in reply to pdjuandi

Guru 29720 points

Hi Peter-san,

My customer doesn't have the tool you suggested however he said TPS65987EVM basically works according to GUI settings that are flashed.
In addition, He re-flashed several times and got the same result.

Could you look into it again?
We suspect TPS65987D opens internal FET when VBUS current is greater than active contract RDO operating current regardless of Peak Current (%).

Best Regards,
Yaita

0 pdjuandi over 4 years ago in reply to K.Yaita

TI__Mastermind 29755 points

Yaita-san,

I took back my statement above as regards to ILIM around 2A with 200% peak current.

You are using 20V instead of 5V, this over-current clamping scheme only applies to PD sourcing 5V on VBUS and not other voltages.

You can read more of this in this Apps. Note on page 9 and the note which mentioned only for 5V is shown below.

Regards,

Peter

0 K.Yaita over 4 years ago in reply to pdjuandi

Guru 29720 points

Hi Peter-san,

Thank you for your reply.
Figure 1 shows "FW OCP Threshold = IoC" and I believe the threshold doesn't depend on Peak Current.
Is my understanding correct?

If the answer is yes, I believe the following is a normal function.
--------------------------------
My customer set Source Capability as the following with TPS65987EVM that is configured as DFP.
When connected to one PD Sink, he confirmed 20V/1A contract is achieved.
Then he increased the load current at VBUS (20V) on purpose, the cutoff (FET open) occurs around 1.2A.
Is it a normal function of TPS65987D?
--------------------------------

Best Regards,
Yaita

0 Hari Patel1 over 4 years ago in reply to K.Yaita

TI__Genius 12700 points

Hi Yaita,

Yes this sounds correct. Peter is out of office for this week and will be able to verify with you when he is back.

Thank you,

Hari

0 K.Yaita over 4 years ago in reply to Hari Patel1

Guru 29720 points

Hi Hari-san,

Thank you for your kind support. I will wait for the feedback.
In addition, I would like to know if we can adjust FW OCP Threshold when VBUS=20V except to change Maximum Current (blue part).
I believe we can't but would like to confirm just in case.

Best Regards,
Yaita

+1 Hari Patel1 over 4 years ago in reply to K.Yaita

TI__Genius 12700 points

Hi Yaita-san,

Yes, that's correct you can only adjust the Maximum current field and the Peak Current for the 20V PDO not the OCP threshold unfortunately.

Thank you,

Hari

0 K.Yaita over 4 years ago in reply to Hari Patel1

Guru 29720 points

Hi Hari-san,

Thank you for your confirmation.
I fully understand.

Best Regards,
Yaita

0 Hari Patel1 over 4 years ago in reply to K.Yaita

TI__Genius 12700 points

Glad I could help!

Interface

Interface forum

TPS65987D: overcurrent protection