Tool/software:
Hi Team,
Test TPS2372-4 EVB,
When using BULLET POE IP SWITCH for power supply testing,
Test output perform power,
IP SWITCH will actively protect mode,
The Startup waveform when the PCB is turned on is as follows:
Hi Kevin,
Thanks for reaching out!
Looks like the red waveform is the VDD-VSS voltage and yellow is the power interface current. Both waveforms look correct on the PD aspect, but I could also see the PD is in auto maintain power signature mode based on the current. It could be the DC/DC IC is not starting up correctly.
One thing you could try is utilizing the PG pin of TPS2372-4 to hold the LM70880 when PD is in inrush mode.
Let me know if it helps. I can invite LM70880 experts to check the schematic together if it does not work. Thanks!
Best regards,
Diang
Hi Kevin,
Thanks for your patience.
From the waveform the auto class is on. I am wondering if you can try disable the auto class by making the AUTCLS pin open (R14 removed). Some PSE may not support auto class.
Best regards,
Diang
