TPS25740A GDNG pin issue

Tino Pan

Intellectual 300 points

Other Parts Discussed in Thread: TPS25741A

Dear All ,

Customer have new question.

After insert the UFP equipment, my client tested the TPS25740A's GDNG pin will output voltage oscillation . What causes this problem?

over 9 years ago

0 Lee E Myers over 9 years ago

TI__Intellectual 1710 points

Can you also probe VBUS. I suspect that VBUS voltage was not detected which would cause the TPS25741A to turn off GDNG.

0 Tino Pan over 9 years ago in reply to Lee E Myers

Intellectual 300 points

Hi Sir ,
Thank you , but I don't think this causes is over voltage protection.

This is my test conditions.
Input Voltage = 5.0V
PCTRL = VAUX
HIPWR = DVDD
EN9V = GND
PSEL = Contact 100K to DVDD
CC pin parallel is 470pF +/- 10%
Short current sensor resistor

0 Lee E Myers over 9 years ago in reply to Tino Pan

TI__Intellectual 1710 points

The TPS25741A not only monitors over voltage but it also monitors under voltage and over current.

I don't see any PD messages on the CC line which suggests that the VBUS voltage is not valid.

0 Patrick Zeng over 9 years ago in reply to Lee E Myers

TI__Intellectual 1090 points

Hi Tino,
It looks like UVLO behavior; I suggest you capture VBUS, DCDC_Out, CC and I_out, it's easier to dig into.

Regards,
Patrick

Interface

Interface forum

TPS25740A GDNG pin issue

Dear All ,

Customer have new question.

After insert the UFP equipment, my client tested the TPS25740A's GDNG pin will output voltage oscillation . What causes this problem?