TPS65994AD: Sourcing 5V/3A with PP_EXT(PP3)

Dave Chang

Expert 5475 points

Part Number: TPS65994AD
Other Parts Discussed in Thread: TPS55289, TPS65994BF

Tool/software:

Hello Support team,

This is FAE Dave supporting industrial PC customers.

I have experienced the problem about sourcing 5V with external path here:

Customer’s system should be the source state machine only, and the output varies from 5V, 9V, 12V, 15V and up to 20V with maximum rating of 30W using our buck-boost TPS55289 controlled by PD controller with I2C.

Here’s the problem, if the high contract is negotiated, the power would switch from PP1 to PP3 using external path for sourcing the voltage more than 9V.

Can we use the PP3 to source the 5V/3A with buck-boost?

As I tested, the VBUS will not be enough to open the Px_GATE_VBUS when we initialized the setting to PP3 for 5V/3A PDO. Thus, PP1 should not be disabled at this criteria.

But, can we do some command to switch from PP1 to PP3?

Ex: I set two PDOs, and both of these PDOs are for 5V/3A, but one is sourcing from PP1 and the other is from PP3.

After buck-boost is enabled, the PDO is shifted from the PP1 one to PP3 one. (This behavior should be the same as high contract negotiated, the only difference is the output voltage being kept at 5V)

Please kindly suggest, thanks for the support.

Best regards,

Dave

over 1 year ago

0 Dave Chang over 1 year ago

TI__Expert 5475 points

For supplement:

Why the behavior is needed?

If 5V/3A is sourcing from PP1(connected to PP5V), the system will have too high load at 5V rail, resulting in heating problem and design cost issue.

Also, the buck-boost will be standby when consuming the 5V power, which is the waste here.

Thanks.

Dave

0 Shubha T R1 over 1 year ago in reply to Dave Chang

TI__Expert 3950 points

Hi Dave ,

Thanks for reaching out.

May I know the PD controller used and please share PJT file.

PP3 can be used to source 5V 3A.

Please share waveforms captured when the issue occurs.

Thanks ,

Shubha

0 Dave Chang over 1 year ago in reply to Shubha T R1

TI__Expert 5475 points

Hello Shubha,

Thanks for support here.

Customer uses TPS65994BF as the controller.

PJT file:Avalue_Kerwin_NUC_ADN_20240805_Ver2.pjt

The buck-boost is ready to output 5V already. (We measured 5V at output of buck-boost)

(At this PJT, I set the PDO1 to PP1, but using Aardvark for dynamic adjustment for PP1/PP3)

But the gate is not opened, thus I am assuming the behavior at Buck-boost side also the I2C are working properly.

Thanks.

Best Regards,
Dave

0 Dave Chang over 1 year ago in reply to Dave Chang

TI__Expert 5475 points

Hello Shubha,

Sorry for the urgent demand.

Is there anything that we need to provide?

Customer is urgently for our support, thanks.

Dave

0 Shubha T R1 over 1 year ago in reply to Dave Chang

TI__Expert 3950 points

Hi Dave ,

Is 13V ( GATE_VBUS when VBUS is at 5V) not sufficient to turn on the power path?

Please share the schematic.

Please share a scope shot of issue faced while using PP1 to source PP1 and while transitioning to 9V/15V/20V.

Thanks ,

Shubha

0 Shubha T R1 over 1 year ago in reply to Shubha T R1

TI__Expert 3950 points

I would request you to please move this thread to Internal E2E.

0 Dave Chang over 1 year ago in reply to Shubha T R1

TI__Expert 5475 points

Hello Shubha,

Thanks. How could we move to internal forum?

If we initialized to use PP3 sourcing all the PDOs, what will happen to PP1?

For the question above, is that when there is no power at VBUS, how can PP3 be opened?

We measure that Vbus being 0V, and VSYS(connected to output of buck-boost) is 5V.

I will let customer measure the waveform, thanks.

Best Regards,
Dave

0 Shubha T R1 over 1 year ago in reply to Dave Chang

TI__Expert 3950 points

Please create a new thread on Internal E2E. Add this thread as a reference

0 Shubha T R1 over 1 year ago in reply to Shubha T R1

TI__Expert 3950 points

1. PP1 will be disabled

2. Is it for Sink case?

Power management

Power management forum

TPS65994AD: Sourcing 5V/3A with PP_EXT(PP3)