• State TI Thinks Resolved
  • Locked Locked
  • Replies 10 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 433 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ40Z50-R1: BatteryStatus register bit 6 changing from discharge/relax to charge

Bill Meyer
Prodigy 20 points
Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQSTUDIO, BQ40Z50, BQ24715

I have an issue with BatteryStatus register bit 6 changing from discharge/relax to charge. What causes this bit to reset and begin charging? Is it a particular level of current flow through the battery stack? Where is this level of current controlled? 

  • 0
    TI__Expert 8365 points

    Bill,

    Once the Current < Quit Current for Chg Relax Time (a parameter located in the Gas Gauging class of the parameters tab in BQStudio) bit 6 of the BatteryStatus register should flip to 1 as the device is now in relax mode. 

    To exit relax and begin charging, Current > Chg Current Threshold must be satisfied.

    Hope this helps, let me know if you have further questions,

    Jackson

  • 0 in reply to Jackson DiGiovanna
    Prodigy 20 points

    Hello Jackson: Thanks for your reply. Once the current is greater than "Chg Current Threshold and bit 6 is reset, how is charging enabled? According to my operation status register bit 0-2, a battery pack has been sensed and both chg and dischg FETS are on. So how does resetting bit 6 complete the circuit and allow charging to take place? 

  • 0 in reply to Bill Meyer
    TI__Expert 8365 points

    Both FETs being on here should complete the circuit and allow charging to take place. Are you saying that you are not able to charge while this is the case? If so, please send me a screenshot of BQStudio as this is happening so I can see the status of all of the registers. Could you also send over your .gg file so I can look at your settings/configuration?

    Thanks,

    Jackson

  • 0 in reply to Jackson DiGiovanna
    Prodigy 20 points

    Hello Jackson: So sorry, I'm working with a colleague in another location and isn't using bqStudio. In fact, all data I have is thru battery communication while in a charger system. Sadly, he isn't reporting all of the registers, just battery status, operation status, charge status, current and voltage. 

    The confusion is the operation status implies both CHG and DISCHG FETs are on and Battery status bit 6 is set. Plus, the charger voltage is ~100mV higher than the battery stack voltage, so we should be charging. Is it possible that when bit 6 of battery status register is set, the CHG and/or DISCHG FETs are NOT on even though operation status bits 1,2 are set claiming the FETs are on?  I'm only basing the FETs on by the operations status register bits 1,2. 

  • 0 in reply to Bill Meyer
    TI__Expert 8365 points

    Hi Bill,

    In general with the FETs on and a charger voltage 100mV higher, I would expect bit 6 of BatteryStatus() to reset. 

    There are two things that at first glace I could see preventing this from happening.

    1. Charge Current Threshold has been raised in the data memory to be above 100mV (its default value should be 50mV)

    2. Some protection has been triggered that is preventing charging from occurring. Could you tell me the status of bits 13 and 14 of OperationStatusA()? these should usually indicate if a protection has been triggered even if we cant observe the status of all the protections registers.

    Going forward it may be difficult to debug without any sort of log file or gg file from BQStudio but ill do my best to find a solution without. Just wanted to give you a heads up on that.

    Thanks,

    Jackson

  • 0 in reply to Jackson DiGiovanna
    Prodigy 20 points

    Hello Jackson:

    I have the gg file. But don't see how to attach. I checked the Charge Current Threshold and it's set to 50mA. The Operation Status is 0x00000187. Bits 13, 14 are 0. 

  • 0 in reply to Bill Meyer
    TI__Expert 8365 points

    Bill,

    At the bottom of the text box, click Insert then Image/Video/File then Upload and then attach the gg file.

  • 0 in reply to Bill Meyer
    TI__Expert 8365 points

    Bill,

    I realized I mistyped the units for Chg Current Threshold which may have lead to some confusion. Obviously this value should be in mA not mV so my apologies for the typo there.

    I would expect that with only 100mV delta from charger to your pack that the current level is not getting above 50mA and thus the device is not in charge mode. Take a look at your current and see if this is the case. Often times, The IR loss along the trace connecting your charger to your pack can result in a significant enough voltage drop to where there is almost no current flowing through this path. 

    If you raise this voltage higher than 100mV above your pack voltage I expect you should see 50mA current flow.

    Best,

    Jackson

  • 0 in reply to Jackson DiGiovanna
    Prodigy 20 points

    Hello Jackson:

    Thanks for your reply. I was told by my colleague told he was able to get past this issue if he is to make the final charger voltage setting in one step instead of ramping. We discovered an unexpected behavior issue on the bg24715 charger controller. If we don't ramp the charger voltage from start to the final value, the charger behaves as a voltage controller for about 500uS before it changes to current control. During this transition, current jumps to 12A and this causes SC flag issues with the bq40z50 fuel gauge.  So now,  if the stack voltage is above 10V, he makes the final voltage change in one step. We actually have two issues with the bq24715.  So I think we can consider this closed for now.