TPS65217: AC and USB switching

na na78

Part Number: TPS65217

The customer intend to use TPS65217 under the following condition.

- Battery is absent
- AC is prioritized over USB

Question
1.
Could AC_EN and USB_EN be turned off automatically if the input absence is detected?

2.
Is it possible that the leak current from USB to AC pin could be flowed when AC_EN and USB_EN are 1? (AC and USB are shorted?)

The reason why they have second question is that they concern possibility of reset
could occur when power input is switched from AC to USB.

3.
Can we switch input from AC to USB without Vsys voltage droped?

BestRegards

over 6 years ago

0 Brian Berner over 6 years ago

TI__Mastermind 30310 points

na na78,

Please refer to this post, where a similar question was asked:

In summary, you should follow the datasheet recommendations and do not use both AC and USB inputs to TPS65217 with no battery is present.

0 na na78 over 6 years ago in reply to Brian Berner

Guru 16770 points

Hi Brian

Thank you for your information.

I found probably relevant application report.
www.ti.com/.../slva901.pdf

According to case A and B from this report, we would need provision even if the input is either AC or USB.
So we need such provision if we use single input path (AC or USB) without battery.

Is my understanding correct?

0 Brian Berner over 6 years ago in reply to na na78

TI__Mastermind 30310 points

na na78,

Yes, it is a best practice to have this provision.

If you do follow solution circuit #3, you do not need to have multiple load switches. You would just need one 2-channel (2 inputs, 1 output) multiplexing load switch.

Power management

Power management forum

TPS65217: AC and USB switching