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Battery monitor with LED outputs

C.A.
Intellectual 375 points
Other Parts Discussed in Thread: BQ2425, BQ2970, BQ40Z50-R1, BQ34Z100-G1

Dear Sir or Madam,


Sorry if I am not in the correct section.


I am developing a 1-cell Li-ion battery charger. Basically, the charger IC will be the BQ2425 and the battery protector will a BQ2970. The battery and the charger will always stay togheter and a load can be connected.

If I understand correctly, the BQ2970 is necessary because the charger has less protection (for exemple, it cannot protect the battery from a short-circuit between the battery and the load).

A feature I need is one or more LED indicating the battery status. With the charger, I have a pin INT/PG or STAT/CHG which can give me the information if the battery is charging or when the charge is finish. With the protection, I can get some information with the voltages at the pins V-, COUT and DOUT. But to display these information on LED, it will need several voltage comparators and probably some logic IC which will take lots of room on my PCB as well as being complex to design.


Does it exist a chip which can monitor the single cell battery in a very simple way (stand alone application, not connecting to a communication bus such as I2C or USB) ? I mean, I would like to connect it to the battery and get logical output signals depending on the status (charging, charge complet, battery full, battery half-full, battery almost discharged, battery dead, etc.). Not necessary 1 LED per information, a blinking LED would be nice as well.

Best regards,


Christian

  • 0
    TI__Prodigy 385 points

    Christian,

    Thanks for your inquiry.

    The features you are requesting are usually things you would find in our gauging products rather than in the protection or monitor device that are intended to act completely independently (protection) or provide information to an existing micro-controller in the system to perform further calculations on (monitor).

    A product like the bq34Z100-G1 or the bq40Z50-R1 might fit your needs. I hope those links prove helpful to you.

    Todd

  • 0 in reply to Todd Vanyo
    Intellectual 375 points

    Dear Todd,


    Thank you very much for your response.


    I had a look on the BQ34Z100-G1 before writing on this forum but I did not know the BQ40Z50-R1.


    About these IC, I do not really understand if a host system is mandatory or not. I can see in the description of the BQ40Z50-R1:

    "...and reports this information to the system host controller over an SMBus v1.1 compatible interface." which makes me think that a host system such as a PC or MCU-based circuit is necessary.


    I have the same question for the BQ34Z100-G1:

    Section 8.3.13 p38: I can see there are some register to write in, in order to configure the LED display which also makes me think I do need a host system as well.


    It would be very kind if you can help me about this point. Sorry, I am a novice in cell charger design.

    Best regards,

    Christian

  • 0 in reply to C.A.
    TI__Prodigy 385 points

    Christian,

    Typically a host system is necessary to provide more reporting capability with the gas gauge. Unfortunately, I don't know the details of those products too well, so I recommend posting your questions on the gauging forum.

    Todd

  • 0 in reply to Todd Vanyo
    Intellectual 375 points

    Dear Todd,


    Thank you very much for your response. Okay, I will try to write there.


    Best regards,


    Christian