BQ29209: CB_EN pin pull up resistor

Stefano Sivera

Part Number: BQ29209

Hi guys,

on the data sheet of the component I see an internal pull up connected on CB_EN pin and I not connect an external pull up but when VIN is disconnected the CB_EN pin increase only at 0,6 V. What is the value of this pull up ?

Thank You

BR
Stefano

over 2 years ago

0 Luis H. S. over 2 years ago

TI__Mastermind 42060 points

Hello Stefano,

I am not sure what the internal pull-up resistor is, it does not seem like it was characterized.

The datasheet does recommend to externally pull it high (Above 2.2-V), like an external pull-up to Vdd, in order to disable cell balancing. Or connect it to GND (below 1-V) in order to enable cell balancing.

Best Regards,

Luis Hernandez Salomon

+1 Luis H. S. over 2 years ago in reply to Luis H. S.

TI__Mastermind 42060 points

Hello Stefano,

I looked more into this and found this old e2e post: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/619720/bq29209-need-resistor-value-for-calculate-leakage-current

Which mentions that if the CB_EN pin is grounded, there would be up-to 200-nA of current. So you could assume that the pull-up resistance is a very high impedance. Any leakage current could potentially pull it low.

Best Regards,

Luis Hernandez Salomon

0 Stefano Sivera over 2 years ago in reply to Luis H. S.

Prodigy 221 points

Hello Luis, thank you for help, I see the post, and I will add the external resistor

best regards

Stefano

Power management

Power management forum

BQ29209: CB_EN pin pull up resistor