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BQ24735 and BQ40z50 FUEL GUAGE BASIC INITIALISATION PROCESS PROBLEM

Chairun
Intellectual 360 points
Other Parts Discussed in Thread: BQ40Z50, BQ24735

Dear Sir,

I am from Qmax, i am using charger BQ24735 and Guage BQ40z50 for monitoring our project. I am giving 16000mv voltage,1024mA current for charging and Watchdog timer is set to 44sec. Updating current and voltage for Each 5 secs, Using the 0x0071 register in fuel guage i am getting and displaying the battery percentage. But sometimes percentage of battery its not going to change, Same Percentage is there for a long time (After 55%). If we reset the device means, it shows different percentage and Chemistry ID after 2 days it is automatically changed to some other ID. How its changing dont know clearly. (Using Chemistry ID : 100). Sometimes FET enable also not work.

So please any one specify step by step initialization process.

I followed these below procedure:

1) Set the Charging Option : b912, Charging Current = 1024mA, Charging Voltage = 16000mV, Input current = 4084mA

2) Update the Current and Voltage for each 5seconds.

3) Enabling the LED_EN (0x0027) in fuel guage.

4) Writing and Reading the 0x0071 Register from Fuel guage and getting the percentage and display.

 

Please specify is Device Reset / FET enable / guage enable want to include in my steps.

 

Thank You,

ARUNKUMAR

  • 0
    TI__Guru 73830 points

    Arunkumar, 

    Are you using the bq24735 as a smart charger where the bq40z50 controls the Charging Current and Charging Voltage over the SMBus? Can you provide a log file showing the problem and also a gg.csv file with the data flash configuration? 

    Tom

  • 0 in reply to ThomasCosby
    Intellectual 360 points

    Thomas,

    Yes I am using bq24735 as a smart charger and bq40z50 for monitoring current and voltage using SMBUS. Please see i attached gg.csv file.

    I am from ANBU, Qmax team. We already sent two cells for getting chemistry id to your office. we are still waiting for your reply for that, meanwhile for the sake of evaluation we are using 0x0100 chemistry id. bq40z50.zip

  • 0 in reply to Chairun
    TI__Guru 73830 points
    You do not have broadcsat mode enabled on the bq40z50, so the device will not send commands to the charger to let it know how much current and voltage to provide. You will need to enable the BCAST bit in the SBS Configuration register. You may also want to reduce the Charging current settings until you get charging to work. Maybe the charger / device are getting into an overload condition and inhibiting charging.
  • 0 in reply to ThomasCosby
    Intellectual 360 points
    I am manually updating the registers of voltage (16000mv) and current (1024mA) for each 5 seconds. so its working, I didnt enabled the BCAST. I am using 0x12 and 0x16 i2c address for charger and fuel guage to communicate. I don't know how to enable sbs configuration register. Would you please guide me with example and solve our problem.
  • 0 in reply to Chairun
    TI__Guru 73830 points

    The BCAST bit is located in the SBs Configuration register in the data flash. Go to the Data Memory screen and select the Settings button. You will find the Sbs Configuration register in the Configuration section. You can select the number (probably 20) and select the BCAST bit and press the Write to Data Memory button. The charger does not support PEC, so you do not need to select the CPE flag to enable packet error checking. The gauge should broadcast the Charging Current and Charging Voltage the the charger over the SMBus.

  • 0 in reply to ThomasCosby
    Intellectual 360 points
    OK Sir. I did as you told like that only.

    But I want to charge my device when it charger and guage is in OFF state. How can i make it ?

    I'll just plugin adapter when it is in OFF state, It must charge the battery.
    (I am updating charge current and voltage in ON case, How can i update the charge current and voltage in OFF case to charge the battery)
  • 0 in reply to Chairun
    TI__Guru 73830 points
    What do you mean by the off state? The gauge should broadcast the Charging Current and Charging Voltage to the charger unless it is in a fully charged condition or certain protection faults are present.
  • 0 in reply to ThomasCosby
    Intellectual 360 points

    I'll make Charger and Fuel-guage both in OFF condition. Then I'll put adapter for charge the battery. I'll not apply any  charging  voltage / current. 

    My Question is : How the Charger will take the charging current and voltage in OFF Condition. If Answer is enabling the BCAST bit means, what is the SBS Configuration register Address. I am manually writing a program to monitor the battery, i am not using your application. So please specify the SBS Configuratiion address to enable the BCAST Bit.

    CONNECTION :

    i.MX51 ---- CHARGER(BQ24735) ----- Fuel Gauge (BQ40z50) ----- BATTERY

                              0x12                                   0x17 / 0x10 / 0x14

     

    How  0x10 and 0x14 is useful for our application. Please specify exactly.

  • 0 in reply to Chairun
    TI__Guru 73830 points
    We do not have an SMBus or MAC command to directly access the SBS Configuration register, but you can access it through direct memory access to the flash memory. We have an applications report on the bq40z50 website to help with this procedure. The smart chargers usually offer a Charge Enable pin or Charge Enable bit in a control word that will allow the host to enable or disable charging. The gauge just sends the Charging Current, Charging Voltage and charging faults to the charger.
  • 0 in reply to ThomasCosby
    Intellectual 360 points

    Manually i setted the charging voltage to 16000mv and charging current to 1024mA.

    After that as per your guidelines, I Enabled BCAST bit, HPE, CPE. After Enabling the current and voltage, it is updating to 10640mv and 0A. (that is taking long time [around 10 mins] initially to update the voltage and current).

    After Switch OFF, If i put charge again means, for updating current and voltage takes long time to update that too current is 0mA and voltage is 10648 mA. [ I have doubt, Whether BCAST bit is telling battery voltage or updating charging voltage]

    How can i make it constant charging voltage 16000mV and charging current 1024mA. Please guide me

  • 0 in reply to Chairun
    TI__Guru 73830 points
    You need to check to make sure that your charger supports Packet Error Checking and set CPE to 0, if it does not. You can check the SMBus with am oscilloscope to verify that the broadcast commands are getting sent to the charger.
  • 0 in reply to ThomasCosby
    Intellectual 360 points

    I Checked in OSCILOSCOPE also

    If i Enable CPE flag with BCAST means, Fuel Guage sent 10496mv &  0V current to charger.
    If i disabled CPE flag with BCAST means, Fuel Guage sent 0v & 0A current is updating always.

    How can i make it smart charger ?

  • 0 in reply to Chairun
    Intellectual 360 points

    In Oscilloscope all the datas are updated, showing the data also,

    I want to charge my battery using your devices (bq24735 and bq40z50). How to make it turn on charger ic in OFF state and update current and voltage to charge battery.

    The Data, What it is updating from the fuelguage to charger  10496mv and 0A is wrong data. So please tell, how to make it smart charger.