BQ78Z100: NR Bit

Mark Philip Felipe

Part Number: BQ78Z100
Other Parts Discussed in Thread: EV2400, BQSTUDIO, , BQ41Z50

Tool/software:

Hi Team, seeking some support on this inquiry.

I have a circuit which is powered by a battery and charged with a charger plugged to the wall. If I am working with battery power and the battery runs out, I want to be able to remove that battery and use a charged one. And at the moment if I do this the device doesn't power on until I plug the charger. After I disconnect the charger, the battery works fine. In chapter 5.2 from the "sluub63a" I read this: "NORMAL Mode: ....The [NR] bit is set, and the system asumes a non-removal battery pack"

I looked for the NR bit in this document and in the bqstudio with the EV2400 connected to my device, and I couldn't find it.
In the "sluub63a" document it says it is a bit from the DA Configuration, and there is no reference to that bit anywhere.

I wanted to ask you if there is a way to program the ChemID parameter into a bq78z100 using an I2C command instead of using the EV2400 for every gauge I use in my product. Thanks

-Mark

6 months ago

0 Jose Couso 6 months ago

TI__Mastermind 27321 points

Hello Mark,

The BQ78z100 is a PACK side gauge (meaning the recommended use case implies gauge and battery are together all the time).
The device will shutdown when the battery is removed from the gauge IC. From shutdown, gauge can only wake up using a charger or applying a voltage on the pack pin.
After wakeup from shutdown, the gauge might have initial OCV gauging errors depending on how stable the measured voltage is (this is a different discussion)

About the NR bit. This is often used in higher cell count gauges that have the sys_present functionality. See below for BQ41z50 explanation.
https://www.ti.com/lit/ug/sluucp8/sluucp8.pdf

Note that the BQ78z100 does not have this functionality.

ChemID can only be uploaded using bqStudio GUI. It requires EV2400 + bqStudio.

0 Mark Philip Felipe 6 months ago in reply to Jose Couso

TI__Genius 10810 points

Hi Jose,

Do we have other mordels models that allow the battery to be removed and, when reconnected, the device continues to function without having to connect the charger? Alternatively, is there any catalog where I can search for these chips?

0 Jose Couso 6 months ago in reply to Mark Philip Felipe

TI__Mastermind 27321 points

Hi Mark,

I would look at BQ41z50. https://www.ti.com/product/BQ41Z50

Also, here's the catalog.

Power management

Power management forum

BQ78Z100: NR Bit