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BQ25798: Is the BQ28Z610 the best solution for a low current 1S application?

Part Number: BQ25798
Other Parts Discussed in Thread: BQ28Z610, BQ34210-Q1

Tool/software:

Hello! We are working on a low current (5mA average, 100mA peak) application that requires 3.3V and 12V with battery backup. Reliability is a mayor concern for the customer.

We were planning to use the BQ25798, with a 1S battery configuration.

The application requires 3.3V for a Microcontroller (MCP) that we plan to obtain from the VSYS output of the BQ25798 charger (adding a buck-boost regulator).

An input power source of 12V will be available to charge the battery and supply the load through the VBUS output, using the Backup Mode of the BQ25798 to supply power uninterruptedly (UPS) from the battery.

Questions:

1- Is the BQ25798 in this configuration the best solution for a charger with UPS (Backup Mode) capability?

2- Is the BQ28Z610 the best Fuel Gauge device to this application?

3- Are there any alternatives to the BQ25798 and the BQ28Z610 with AEC-Q100 compliance?

Thanks in advance,

Lien

  • Hello Lien,

    1- Is the BQ25798 in this configuration the best solution for a charger with UPS (Backup Mode) capability?

    Yes, i recommend using BQ25798 if backup mode is required.

    2- Is the BQ28Z610 the best Fuel Gauge device to this application?

    I will loop in the person that supports this device.

    3- Are there any alternatives to the BQ25798 and the BQ28Z610 with AEC-Q100 compliance?

    We do not have any alternative battery chargers with AEC-Q100 compliance.

    Best Regards,

    Christian

  • Hello Lien, 

    The BQ28Z610 is not Q100 approved. The only battery gauge with Q100 compliance is the BQ34210-Q1. 

    Regards, 

    Jonny. 

  • Thanks Jonny

    I am checking that BQ34210-Q1 says "for Rarely Discharged Batteries"

    So that means I can not use it to daily cycling charging and discharging?

  • Hello Lien, 

    Yes the BQ34210-Q1 is intended for rarely discharged applications. 

    Regards, 

    Jonny. 

  • Hello Jonny,

    Could you please tell me what is the difference in the usage mode with this device? Why shouldn't we use it in a cycle-use application? Is it because of the learning process to estimate the End-of-Service (EOS) and the other capacity-related parameters?

    Based on your last answer, I understand that we should use:
      a- BQ28Z610 in applications with cycle charging use of the battery,
      b- BQ34210 in applications with stand-by charging use of the battery.

    Is that correct?

    Regards,

    Lien

  • Hello Lien, 

    My apologies, I have talked this over with the team, and the BQ34210-Q1 can be used for normal applications. This gauge can operate the same as a CEDV gauge. One thing to note here is that the maximum voltage you can use for this gauge is 5.5V. 

    Regards, 

    Jonny.