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BQ34110: Host-reported temperature

Aki Lankinen
Prodigy 70 points
Part Number: BQ34110
Other Parts Discussed in Thread: BQ25792

Hi,

In the chip datasheet is written in page 80 the following: "3.13 InternalTemperature ... This function can be useful as an additional system-level temperature monitor if the main Temperature() function is configured for external or host-reported temperature.”

How can I configure Temperature() function for host-reported temperature?

  • +1
    TI__Guru 57697 points

    The Temperature() command is read-only. Therefore the bq34110 cannot accept/support host-reported temperature.

  • 0 in reply to Shirish
    Prodigy 70 points

    OK, thanks for the reply. Do you have a pin compatible (or close) fuel gauge that can use host-reported temperature?

    Another option is that we continue to use internal temperature sensor. We have a battery pack of two Li-ion cells that have integrated NTC that is connected to BQ25792 charger as we think it's more important that it has accurate temperature information in case of over heating. BQ34110 is located on a PCB that is next to battery pack. Can you estimate how much this effects to SoC accuracy over -20 to +50 Celsius degrees range? Or what would be the best method to measure the accuracy?

  • 0 in reply to Aki Lankinen
    TI__Guru 57697 points

    Hello Aki,

    The option to write host-reported temperature to the fuel gauge is available only in some single cell gauges. 

    For best results the thermistor must be closely coupled to the battery. Assuming that the battery has a NTC that is compatible with bq34110, I would recommend that you use the bq34110 to control the charger.

    See bq34110 TRM section 2.9 Charging and Charge Termination for details. There are a lot of settings available.

  • 0 in reply to Shirish
    Prodigy 70 points

    Hi Shirish,

    That was new information for me that it is possible to use BQ34110 to control charger. Anyway for now we will stick to the current plan and use internal temperature although it is not optimal. 

    Any hints for the accuracy measurements?

  • 0 in reply to Aki Lankinen
    TI__Guru 57697 points

    Hello Aki,

    At close to room temperature accuracy will be ok, but for high and low temperatures self heating of the battery will cause error in temperature measurement if the thermistor is not closely coupled.