TPS546C20A: We want to know how to test PMBus communication.

kang byungchur

Part Number: TPS546C20A

[Test environment]
1. We purchased "TPS546C20AEVM1-746" to use "PS546C20A".

2. We have successfully tested VOUT from 0.35V to 1.6V in the following environment.
"TPS546C20AEVM1-746" - (USB-TO-GPIO) - "PC (FUSION_DIGITAL_POWER_DESIGNER)"

3. Next, "MCU (ATmega128A) Test Board" was connected instead of PC as in the following environment.
"TPS546C20AEVM1-746" - (2 wire Cable) - "ATmega128A Test Board"

[Question]
Q. We want to check only the PMBus communication test between "PS546C20A" in EVM and MCU (ATmega128A-i2C)
     Can I connect only "CLK" and "DATA" like the attached file for this?
     Or do I have to connect the other two lines (CNTL, SMBALRT)?
       (But we will not confirm until "VOUT" yet)

over 5 years ago

0 JohnTucker over 5 years ago

TI__Guru**** 191445 points

Kang,

I think CNTL is only for manually disabling the output depending on the state of ON_OFF_CONFIG and is not needed to test the PMBus.

I think SMBALERT is just used like an interrupt to alert of fault conditions, and is also not needed to test the PMBus interface.

Only the 2 wire Data and CLK signals are needed.

Our team will verify this today.

0 JohnTucker over 5 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Kang,
Yes, only those two pins are needed for communication over the PMBus.

But their source needs to have pull-ups, or they will need to add pullups to the TPS546C20A part’s BP3 supply.

Power management

Power management forum

TPS546C20A: We want to know how to test PMBus communication.