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BQ25892: BQ25892

Redwood
Expert 1060 points
Part Number: BQ25892
Other Parts Discussed in Thread: BQ28Z610

Hi, 

My end goal is to develop a battery management firmware with charger and gauge. I am looking for an example design. 

In my previous questions,

I found the driver functions for charger( BQ25892)  such as https://github.com/tibms/bq2589x.

I found the driver functions for gauge ( BQ28z610) such as https://github.com/tibms/kernel-4.4/tree/release/drivers/power/bq28z610

BUT, what I am looking not "DRIVER FUNCTIONS", I am looking for "APPLICATION" example. Could you send me a link?

If these driver functions exist, there should be the Application Program somewhere which are using these driving functions : 

  1. for charger( BQ25892)  such as https://github.com/tibms/bq2589x.
  2. for gauge ( BQ28z610) such as https://github.com/tibms/kernel-4.4/tree/release/drivers/power/bq28z610

Please see the example of battery charging profile. Based on such a given battery charging profile, I would like to write an application which charges the battery. I AM LOOKING FOR AN EXAMPLE. ideally with the charger ( bq25892) and the gauge (bq28z610). If not, any other charger and gauge is also fine. 

Thanks and best regards, 

  • 0
    TI__Guru**** 166546 points

    Redwood,

    I am not aware of an application example with software that uses this charger and gauge.  Below are my thoughts on developing such an application:

    Hardware:

    Charger - use default application schematic except for TS pin being connected to NTC.  The TS pin needs matching resistors (e.g. RTOP=RBOTTOM=10k) from REGN to TS to GND.  This disables the charger's JEITA charge profile.

    Gauge - use default application schematic

    Software:

    Charger - I2C write to disable watchdog timer or set to periodically update WD timer bit and also disable charger termination (NOTE:  You can use the charger's termination feature and modified JEITA charge profile but when in JEITA warm, termination when Icharge <ITERM is disabled.)

    Charger - I2C write to set input current limit register if not correct per PSEL pin or ILIM resistor (can also disable ILIM resistor) to provide both SYS load current and BAT charge current (charge automatically prioritizes SYS load current over BAT charge current).

    Charger - I2C writes to set battery regulation voltage, charge current, etc.

    Charger - periodically monitor status/faults and make I2C register changes if necessary (charger is largely self sufficient/protective so minimum work here)

    Gauge - constantly monitor battery temp and use I2C write to change charger's battery regulation voltage or charge current per charge profile.

    Gauge - constantly monitor battery voltage and battery charge current as they reach battery regulation voltage and termination current then disable charger charging when reached

    Gauge - when battery voltage droops below a fixed value (e.g. VBATREG-200mV), I2C write to charger to resume charge. 

    I hope this helps.

    Regards,

    Jeff

      

  • 0 in reply to Jeff F
    Expert 1060 points

    Thanks for the answers. 

    JEFF =  Charger - I2C write to disable watchdog timer or set to periodically update WD timer bit and also disable charger termination (NOTE:  You can use the charger's termination feature and modified JEITA charge profile but when in JEITA warm, termination when Icharge <ITERM is disabled.)

    REDWOOD =  WHAT DO YOU MEAN WITH (  You can use the charger's termination feature and modified JEITA charge profile but when in JEITA warm, termination when Icharge <ITERM is disabled.) ) which document explains "JEITA charge profile"  and "JEITA warm"

    I can not follow up your answers based on the datasheet of this part. Can you guide me how to connect with you? which documents, application notes I should read in order to understand the terminology you are using above.

    How can I post the same question for linux users. I think more detailed answers may come from the application developers on linux platform by using the drivers listed in my previous post. 

    I think There are following users in this forum: 

    1- Users for Device level

    2- Users for Linux Driver for the parts

    3- Users for Linux Application for the parts

    I am more interested at application level developers by using these devices ( charger and gauge devices ). 

    How should I post in these three level for my charger(bq25892) and (bq28z610)?

    Thanks and best regards

  • 0 in reply to Redwood
    TI__Guru**** 166546 points

    Redwood,

    JEITA is an acronym for an industry standard, LiIon charge profile that has been used for over 10 years..  It is the charge profile that you are proposing.  The BQ25892 uses a modified form of your profile. But if the gauge is imbedded in the pack, you cannot use the BQ25892 TS feature and must use matched resistors to disable the feature.

    Regarding posting, for category, this is the correct forum.  I am not a programmer so I do not know programmer forums.   I assume GitHub has a forum for the drivers.

    Regards,

    Jeff