BQ25619E: BATSNS connection with load switch

Maxime GUILLOT

Prodigy 190 points

Part Number: BQ25619E
Other Parts Discussed in Thread: BQ25619

Tool/software:

Hello TI,

You can find the part of the schematic below:

I was wondering how to connect BATSNS pin.

The best way is to connect to point B, near the battery connector and after the load switch, right?

But in case the load switch is turn of and no power is going to the BQ25619, is he charger can handle a voltage (VBAT) on BATSNS pin?

Thank you

8 months ago

0 Michael Emanuel35 8 months ago

TI__Mastermind 41075 points

Hello,

Connect the BATSNS pin in a kelvin connection as close as possible to the battery. However, please disable charge before disabling the load switch and enable the load switch before enabling charge.

Regards,

Mike Emanuel

0 Maxime GUILLOT 8 months ago in reply to Michael Emanuel35

Prodigy 190 points

Hello,

Understood but my question is more:

Is there any risk for the BQ to have BATSNS=VBAT=3.8V whereas VBAT=VUSB=0V?

Current leakage at the BATSNS pin for example?

Thanks

0 Maxime GUILLOT 8 months ago in reply to Michael Emanuel35

Prodigy 190 points

Is there an esd diode inside the BQ between BATSNS and VBAT or VUSB?

0 Michael Emanuel35 8 months ago in reply to Maxime GUILLOT

TI__Mastermind 41075 points

After further reflection, is there a reason for the load switch? You can turn off the BATFET with I2C.

Regards,

Mike Emanuel

0 Maxime GUILLOT 8 months ago in reply to Michael Emanuel35

Prodigy 190 points

Unfortunately because Tshipmode duration (1s) is too long for our application.

0 Maxime GUILLOT 8 months ago in reply to Michael Emanuel35

Prodigy 190 points

Hello,

I have tested to applied a voltage on BATSNS pin with VBAT=VBUS=0V and the result is that VSYS=VBATSNS=4V.

0 Michael Emanuel35 8 months ago in reply to Maxime GUILLOT

TI__Mastermind 41075 points

What if you lower BATSNS to 3.8V and 3.9V? It appears the BATSNS line may provide the reference for the SYS voltage. If you want the SYS voltage at MINSYS, try placing the BATSNS before the load switch. However, placing before with charge enabled will charge and discharge the output capacitor.

Regards,

Mike Emanuel

0 Maxime GUILLOT 8 months ago in reply to Michael Emanuel35

Prodigy 190 points

I want the SYS voltage at 0V when switch off (VBUS=VBAT=0V). Then BATSNS has to be connected to the drain of the switch transistor.

0 Michael Emanuel35 8 months ago in reply to Maxime GUILLOT

TI__Mastermind 41075 points

If VBUS and VBAT are 0V, there will be no power source to the device. It should not matter where BATSNS is placed in regard to that inquiry.

Regards,

Mike Emanuel

Power management

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BQ25619E: BATSNS connection with load switch