TPS25762-Q1: TPS25762-Q1 EVM: Unable to get output from configuration file

Hi James,

Your procedure is correct.  What version of the EVM do you have?  Near the TI logo, there should be a mark "TPS25762....EVM."  Can you share this information along with the text below it?

Thanks,
Eric

Hi Eric;   Near the Logo is IPP021 Rev A.   I guess I had two tickets open (was having issues accessing your cloud based GUI this morning - network issues I guess), so I responded to the first because I got confused which issue I was addressing.   In any case, here is what I wrote to Ke Wang:   It does have a follow up question which I guess is intended for you:   My collegue changed out the power supply, with all the circuitry connected.   I am using a USBC simulated load EVAL  :  https://www.digikey.com/en/products/detail/analog-devices-inc/EVAL-CN0581-EBZ/21725124?s=N4IgTCBcDaIKIDUCCAZAtAYQHIAYCsAHAIxpwBCAWiALoC%2BQA  .  In the middle of this I am using a USB Digital Tester (J7-C) and when I returned the tester had power, whereas before it did not.  I did check the voltage values by setting dip switches on the load board and 12V and 15V did come up, indicating that the flash had worked.  I have noticed something is finicky however.  I am using an electronic load device that I use in conjunction with the similated load board - which basically reports allowed currents and voltaged.   Sometimes I would have the USB tester light up but even though the electronic load was enabled, I would see no current sourced.  Sometimes to address this, I would unplug and then replug the Simulated Load board from the USB tester and a current would appear.  I think this is indicating that there is a communication issue between the source and load boards.    In terms of the network, I was finally able to log in.  I am not certain what was going on this morning.  I think I agree with you that it was probably the network on our end as I was even having issues logging into Analog Devices.   I do have a follow up question regarding this kit.   It has a pretty big footprint and supports things that I don't need.   Is there a schematic with a bare bones execution without all the jumpers or excess ICs and passives I would need to act as a programmable source.   Difficult for me to tell what is essential or not, or is it all essential in which case would probably not work for us.

Expected Behavior?   When I set the sink device to a higher current threshold than the source device advertises,  say, 12V @ 2A, when it is limited by source to 1.5A, the source device only puts out 5V with no current delivery, even if the actual load is well below the advertised source current threshold.   The sink device is not smart so in effect does not really negotiate but simply says this is what I am and this is what I need.  I assume real devices on both ends would try to negotiate currents and so would actually put out the correct voltage at an acceptable current limit of the device.  What I would not like to see is people plugging in devices that may be over-rated, and the device simply not working, and clients coming back to us with complaints.

Hi James,

For a more barebones schematic, please refer to this reference design: https://www.ti.com/tool/PMP40934.  There are two 1x3 headers that you can also disregard. They were for testing purposes only.

It sounds like a few things may be going on between the source, sink, and electronic load.

James Carter said:

 Sometimes I would have the USB tester light up but even though the electronic load was enabled, I would see no current sourced

James Carter said:

the source device only puts out 5V with no current delivery, even if the actual load is well below the advertised source current threshold

The PD source will output a fixed voltage.  The amount of current draw is up to the electronic load.  This sounds like there is an open circuit somewhere in the loop.

I'm not familiar with your sink board.  The source will only advertise what it's programmed to.  Even if your sink is programmed to 12V/2A, the PD negotiation will only show 12V/1.5A offered.  From here, the sink decides if 1.5A is enough or not.  It can't request 2A if only 1.5A is offered.  It sounds like your sink is selecting 5V by default here, but I'm not sure.

One idea - what happens if you take the USB tester out of the loop?

Finally, if there continues to be issues, I suggest getting a tool that can decode the PD traffic.  This makes it easy to see what the source is offering and what the sink device requests for power.  This way there's no guessing who is doing what.

Regards,
Eric

Thanks Eric:

It looks like the bare bones design does not have the capability to be configured (at least in the same manner) as the orignal demo board.  There is no USB Micro connector on the board.   How would this board be configured?