BQ25170: Iset RC Filter at low charge current (10mA): how to design?

win.chRene Hug

Part Number: BQ25170

In our application, the charge current has to be 10mA.

datasheet bq25170: For charge currents below 50 mA, an extra RC circuit is recommended on ISET to achieve more stable current signal.

I didn't find a schematic and calculations for this RC filter.

Thanks for helping-

Rene

over 2 years ago

0 Bill Johns over 2 years ago

TI__Guru* 75916 points

Hi Rene

The BQ25170 has preformed will at low currents without the RC circuit.

Recommend adding a position on the PCB for RC circuit as a precaution but not populating.

0 win.chRene Hug over 2 years ago

Prodigy 100 points

Hi Bill
It would be helpful if there were more precise details in the data sheet. I only want to place the RC filter if it would be necessary, otherwise I leave it out because space is tight anyway!
If an RC filter were necessary, how would it have to be dimensioned?

0 Bill Johns over 2 years ago in reply to win.chRene Hug

TI__Guru* 75916 points

Hi Rene

Things to look for to determine is the RC is needed would be ripple or noise on the ISET pin and ripple / noise in the output current.

The standard value for the RC is 4700pf and 2k.

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BQ25170: Iset RC Filter at low charge current (10mA): how to design?