BQ79616-Q1: Cell balance using external mosfet.

santhosh gowda

Prodigy 70 points

Part Number: BQ79616-Q1

Hello Team,

Can we use external MOSFET for above 300mA cell balance current?

over 1 year ago

0 Quentin Silic over 1 year ago

TI__Expert 6980 points

Hello,

Yes, you can use external MOSFET for above 300 mA CB current

Best,

Quentin

0 santhosh gowda over 1 year ago in reply to Quentin Silic

Prodigy 70 points

Thanks for the reply. I got the circuit from application note, but there is not much explanation.

What is the resistor value required for Rbias ? And how to turn ON external MOSFET?

0 Quentin Silic over 1 year ago in reply to santhosh gowda

TI__Expert 6980 points

Hello Santhosh,

From the circuit you can derive that the Vgs of the external MOSFET will be Vgs = Vcell(Rbias/(2Rbias+Rdson)).

The point of Rbias is to minimalize the effect of Rdson. Rdson is already small, so an Rbias of around 500 Ohms would make the effect of Rdson almost zero and therefore Vgs would be Vgs ~= Vcell/2.

The MOSFET will turn on when Vgs is greater than the Vth of the MOSFET. This will be in the datasheet of the MOSFET that is chosen for this external circuit.

Best,

Quentin

+1 santhosh gowda over 1 year ago in reply to Quentin Silic

Prodigy 70 points

Thanks.

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BQ79616-Q1: Cell balance using external mosfet.