4 Replies Latest reply on Sep 21, 2020 7:55 AM by ShifangZ_26

    On the CYPD3125 how do I maintain consumer path power when dropping VSYS?

    MaKe_4459911

      We have the CYPD3125 setup as a DRP.  We supply Vsys (3.3V) to the 3125 when our product is turned on.  When we turn off we still want power supplied to the product for charging the battery.  When we're sinking 5V from the USBC connector (from a USB2.0 connector) and we turn off our product so that VSYS goes away, we see Vddd droop until it switches over to VBUS and then it returns to 3.3V.  But before it switches over it turns off the consumer path FETs so that we lose power to our battery charger.  Here's the trace:

       

      You can see Vddd droop with Vsys until it switches over to the internally regulated Vbus.

       

      Is there a way to keep the consumer path (Switched VBUS) from shutting down?

       

      After a few 100ms we will sometimes see the consumer path turn back on but often the CYPD3125 doesn't seem to be executing code (we have a flashing LED indicating that software is running on the 3125).

       

      Thanks,
      Mark