TPS2544: TPS2544 Vbus drop for 320ms

Oliver Lin

Part Number: TPS2544

Hi team,

Customer found a behavior that not matching the datasheet. We saw a 320ms voltage drop. This doesn't match the tdischarge (2 seconds).

Could you please help me understand the voltage drop on Vbus for 320ms?

EN and ISEL are high for all time

We had probe Vbus_out, CTL1, CTL2, CTL3

over 4 years ago

0 Adam Mc Gaffin over 4 years ago

TI__Mastermind 29275 points

Hi Oliver,

Do you have the ability to measure the FAULT pin? Wonder if there is a fault being measured that is causing for the voltage on VBUS to discharge.

Also, what is the purpose for starting in DCP_Auto, then transitioning to CDP for a second before transitioning to SDP?

0 Oliver Lin over 4 years ago in reply to Adam Mc Gaffin

TI__Expert 3465 points

Hi Adam,

Sure, I will let customer to share the information and get back to you.

0 Oliver Lin over 4 years ago in reply to Adam Mc Gaffin

TI__Expert 3465 points

Hi Adam,

Customer had captured the FLT# pin, it seems no FLT was triggered as below captured.

It seems customer is using DCP auto and switch to other mode, that will enter discharge mode(2s), and that will cause the USB device connection lost, so customer wants to switch other behavior, maybe CDP and SDP2 to avoid the discharge state.

But so far we are not able to explain we are seeing the short discharge time 320ms. Could you please help share any comment on this?

0 Adam Mc Gaffin over 4 years ago in reply to Oliver Lin

TI__Mastermind 29275 points

Oliver,

I cannot comment on why the discharge state is only 320ms

However, if the customer does not want the system to discharge at all, then they should use CDP and SDP2 to avoid the discharge state

Power management

Power management forum

TPS2544: TPS2544 Vbus drop for 320ms