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BQ25619E: How to generate an initial charging pulse with charger config.

Ravi Gohel
Prodigy 20 points
Part Number: BQ25619E
Other Parts Discussed in Thread: BQ27427, BQ27426

Hi,

I want to charge the battery which is having internal cut-off like 3.0 V. below 3.0V there is no output voltage and it is showing 0V from battery so I need to generate a pulse to take it out from its cut off voltage so it can start charged. If battery voltage is not less than its cut-off, it is charging as per configuration. What configuration should be done in bq25619e to take out battery from its cut-off and start the charging normally?

Thanks

Ravi Gohel  

  • 0
    TI__Mastermind 41905 points

    Hi Ravi,

    Battery charger output will be supplied above V_BAT_SHORT. I suspect your protector is cutting of the battery from the circuit. Please refer to your battery protector specification to turn off the protector to allow charging to happen.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 20 points

    Hi Mike,

    If we do not turn off the battery protector and with the combination of BG25619 and BQ27427 is it possible to charge the battery? Please refer to the attached snap of schematic below.

    Also can we set the cut-off of the battery using fuel-guage?

    Battery also gets draining when main power/adapter power is connected.

    Thanks

    Ravi Gohel

  • 0 in reply to Ravi Gohel
    TI__Mastermind 41905 points

    Hello Ravi,

    For the schematic review, is TS connected to a thermistor? If not, you will need to bias TS properly for charge to happen.

    Can you please capture a waveform of VBUS, SW, VBAT, and VSYS when the charge is not happening? Also, can you please capture a waveform of VBUS, SW, VBAT, and ICHG when the charge is not happening? Also, what is the STAT pin when this is happening?

    Can you try toggling CHG_CONFIG Bit REG01 to see if this starts charging?

    Also, what is the trigger to close the protector of the battery you have?

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 20 points

    Hello Mike,

    1) Is TS connected to a thermistor?

    Ans. Yes battery TS pin is connected to the TS pin of fuel-gauge. From the battery charging configuration we've ignored TS bit.

    2) Can you please capture a waveform of VBUS, SW, VBAT, and VSYS when the charge is not happening? Also, can you please capture a waveform of VBUS, SW, VBAT, and ICHG when the charge is not happening? Also, what is the STAT pin when this is happening?

    Ans. I am on this to collect every data.

    3) Can you try toggling CHG_CONFIG Bit REG01 to see if this starts charging?

    Ans. Yes I have tried toggling CHG_CONFIG bit. but as no voltage at BATSENS or BATPIN from battery, no charging is happening.

    We have made new chagnes as per FAE suggestion and updated the schematic. Can you please check the schematic from the original question perspective?

    Thanks,

    Ravi

  • 0 in reply to Ravi Gohel
    TI__Mastermind 41905 points

    Hi Ravi,

    1) The TS pin is properly configured now. 

    2) Waiting on your result.

    3) You need to find a way to wake up your protector. It appears that the protector is enabled and you cannot charge the battery. What condition is causing the protector to be enabled? I need to see the waveforms to confirm the VBUS, SW, and VBAT behavior.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 20 points

    Hi Mike,

    The waveforms are taken when battery is below its protector cut-off. which is 3.0

    The above first waveforms are between VBUS (Yellow) and VBAT (pink). VBAT voltage is 1.608V.

    The above second waveforms are between VBUS and SYS (pink). SYS voltage is 3.812V.

    Let me know if other waveforms you need.

    Regards,

    Ravi

  • 0 in reply to Ravi Gohel
    TI__Mastermind 41905 points

    Hi Ravi,

    Unfortunately it looks like the battery voltage is going up but the protector is cutting it off. Please remove/bypass the protector and see if you have the same issue. In addition, please charge the battery above the protector cutoff and see if you have the same issue.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 20 points

    Hi Mike,

    I have removed the BQ27427 fuel gauge and tried to charge the battery which is below its protector cut off, this worked and battery came out from its cut off voltage. It seems like the battery charger is trying to charge but fuel guage is preventing it. With the normal battery voltage between 3.5 to 4.2V also I am not able to charge the battery due to fuel gauge. Is there any limit which is set due to which the fuel guage does not charge the battery.

    My battery configuration is 4.2 V max and 7000 mAh capacity.

    Fuel gauge configuration is set as mentioned below :

    Gas Gauging State 82 6 Design Capacity 7000 mAh

    Chemistry profile is 1202.

    I have just set two parameters, please suggest any other parameter needs to be set or any changes required in schematic.

    Regards,

    Ravi

  • 0 in reply to Ravi Gohel
    TI__Mastermind 41905 points

    Hi Ravi,

    This seems like a gauge related question. I am handing it over to the gauge team.

    Regards,

    Mike Emanuel

  • 0
    Prodigy 20 points

    Hello Guage team,

    Please help on the issue.

    Best Regards,

    Ravi

  • 0 in reply to Ravi Gohel
    TI__Mastermind 26291 points

    Hello Ravi, 

    I recommend referring to the BQ27426 Quick-Start Guide and at a minimum configuring the parameters in section 4 "Configuring Gauge Parameters". This document is for the BQ27426 and not the BQ27427, but most everything in this document is applicable to the BQ27427 fuel gauge. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 20 points

    Hi Jonny,

    What if I shutdown the fuel gauge. Will that shut off the LDO output and make VDD 0. Currently VDD is 1.8V. Will that impact to the battery to discharge less and charge it?

    Currently I am trying to shutdown the fuel gauge after enabling shutdown. Fuel gauge control status is high byte 0x8C and low byte is 0x20. So, shutdown is enabled but fuel gauge is not getting shut down. I am saying this because VDD is still 1.8V. Let me know if there any other way to check that the fuel gauge is shut down.

    Thanks,

    Ravi

  • 0 in reply to Ravi Gohel
    TI__Mastermind 26291 points

    Hello Ravi, 

    Referring to the TRM, when the gauge is in shutdown mode, the LDO output will be disabled. Please see the image below taken from the TRM. 

    Additionally, if the gauge is in shutdown mode, you will not be able to communicate with the gauge. Please ensure that you are sending the shutdown enable command before sending the shutdown command. Additionally, please ensure that you are not toggling the GPOUT pin, otherwise the gauge will exit shutdown. I just tested this on my EVM here, and when the gauge was in normal mode, the voltage across VDD and GND was ~1.799V, then when the gauge was sent to shutdown mode, the gauge no longer was communicating, and the voltage across VDD and GND was 0V.

    Regards, 

    Jonny. 

  • 0
    Prodigy 20 points

    Hi Jonny,

    It was the Voltage booster which was draining the more power than the charger power. So, when I turned off the voltage booster. The charger is now charging the battery from its cut-off as well as when in normal state. I am also shutting off the fuel gauge to give extra charge to charge with faster rate.

    Thank you,

    Ravi