• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 72 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS25730: conditions for SINK_EN active low

Nick Kettman
Prodigy 10 points
Part Number: TPS25730
Other Parts Discussed in Thread: TPS25762DQ1EVM

Tool/software:

What are the conditions for the SINK_EN pin to transition to the active low state?

I'm observing SINK_EN and PPHV pin behavior on the TPS25730EVM. The EVM is configured for 9V minimum voltage (ADCIN1 decoded value = 1) and 9V maximum voltage (ADCIN2 decoded value = 1).

When I connect a USB PD source capable of 9V, I see PPHV rise to 5 V (vSafe5V), then SINK_EN transitions from high to low, then PPHV transitions from 5 V to 9 V.

If SINK_EN is intended to enable a downstream load, shouldn't this signal transition to active low after the PS_RDY message has been received from the PD source? The PS_RDY signal wouldn't be sent until the source has reached the agreed voltage in the PD contract.

Ch 2: PPHV
Ch 3: SINK_EN

My PD source is the TPS25762DQ1EVM.

  • 0
    TI__Guru 63591 points

    Hello,

    Nick Kettman said:
    When I connect a USB PD source capable of 9V, I see PPHV rise to 5 V (vSafe5V), then SINK_EN transitions from high to low, then PPHV transitions from 5 V to 9 V.

    I am looking at the figures in the datasheet and your observation is correct.  The SINK_EN is related to the implicit 5V contract (USBC where the current requested is based upon the Rd presented by the sink).

    https://www.ti.com/lit/ds/symlink/tps25730.pdf#page=44

    Nick Kettman said:
    If SINK_EN is intended to enable a downstream load, shouldn't this signal transition to active low after the PS_RDY message has been received from the PD source?

    This supports sources which are not PD capable.  

    Regards,

    Chris