BQ25171-Q1: Charger IC solution of NiMH charging Request

Hardy Xue

Part Number: BQ25171-Q1
Other Parts Discussed in Thread: BQ24400, BQ2002T, BQ24105

Hi Team,

My customer has a NiMH Battery Charging requirement on NAS application.

The NiMH Battery is 3S1P.

Power Capacity of AA Battery: 3S1P: 2200mAh /3.6V

Charger Temperature at 50C

Customer is surveying related solution and have some questions as below.

How to reach different battery Inside resistance balance in charging? or need other Charging IC could achieve. Let me know have some choice.
If there are 2 fully charged batteries + 1 dead battery series in system, what is the charger's behavior?
Have other suggestion solution with I2C or SPI also easy to use and low cost
If no need Host control, Have other good choice that easy to use and low cost?
Do we have other smart battery feature solution can introduce to customer?

Best regards,

Hardy

0 Nick Brylski over 4 years ago

Hello Hardy,

BQ25171-q1 does not support any balancing of cells. Balancing generally not needed for NiMH, see Kedar's post here: e2e.ti.com/.../cell-balancing-for-ni-mh-battery-in-series
The charger will only see the cells top of stack voltage. Does not look at individual cell voltages. Behavior depends on whether intermittent charge has been enabled.
BQ25171-q1 will be the simplest option for 3 cell NiMH. There are some more options you can consider like bq2002t, bq24400, or bq24105.

Best regards,

Nick

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