TPS25750: battery hotplug

Walker Wei

Part Number: TPS25750
Other Parts Discussed in Thread: BQ25792

We are using tps25750+bq25792.

No eeprom.
Firmware can be update by MCU through I2Cs.

Is it possible to support this case:
1)Sink Only
2)When battery present, enable PD charging and the output of bq25792's SYS pin.
3)When there is no battery, keep the PD status and keep the output of bq25792's SYS pin.
4)When connect the battery again, back to the 2) situation.

How to config the HW and SW?

over 4 years ago

0 Ghouse Mohiuddin23 over 4 years ago

TI__Expert 8330 points

You can follow reference design USB-PD-CHG-EVM-01 Evaluation board | TI.com for this.

0 Chuck Branch over 4 years ago

TI__Mastermind 33821 points

Wei,

1. Sink only is supported

2. Battery present enable and configuration is supported

3. No battery present, pd connection and output is supported

4. For hot plug, I am going to share this with the BQ25792 support team. I am not 100% certain of the answer.

0 Michael Emanuel35 over 4 years ago in reply to Chuck Branch

TI__Mastermind 42375 points

Dear Wei,

For 4, are you asking if you reattach a battery will there be PD charging and SYS output?

Thanks,

Mike Emanuel

0 Walker Wei over 4 years ago in reply to Michael Emanuel35

Prodigy 150 points

We are designing a production which support replacing the battery during running.

So the SYS output must be kept when USB charger is connected.

It is the best to keep PD charging status.

But falling back to safe 5V charging is also acceptable if there are some difficulties.

Maintaining BQ25792's SYS pin power output is the key.

So for 4, I'm really asking is it possible to keep the SYS output when plug or unplug the battery?

And on the other hand, will there be some unstable situations for SYS output when charging voltage falling back to 5V?

+1 Michael Emanuel35 over 4 years ago in reply to Walker Wei

TI__Mastermind 42375 points

Dear Wei,

Please read the following FAQ about the BATFET and how it affects the system and battery voltages: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1049317/faq-how-does-the-batfet-work-in-the-bq25790-bq25792-bq25798-and-bq25672

Please be careful to manage inrush/outrush current from the plug in of the battery.

Thanks,

Mike Emanuel

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TPS25750: battery hotplug