Improper behavior of DSG PIN in Bq34Z950

Swapnil,

Have you sent the IT Enable command to allow the device to take over control of the FETs? If not, you can send a MAC command 21. One other thing to check is whether your SYSPRES input is connected to PACK- to enable the FETs. You can also try sending the FET override command to turn the FETs on. (see the attached screen shot)

If the FETs are off, then it would be normal for the DSG pin output to be low until voltage is applied to Pack+.

Tom

Dear ThomasCosby,

Mostly all MAC commands can be used in FULL ACCESS or UNSEALED mode.

I am not using TI Gas guaging software but established SBS communication using micro controller and when I send MAC commands, response I get is 0xFF. I think I am in SEALED mode and don't have default keys to enter FULL ACCESS or UNSEALED mode. Will you mail me these default keys? (mail ID: swapnil.misal@electronicaems.com)

Can EV2300 interface board and software which is available for bq20z95/bq29412 battery management be used for BQ34Z950 testing?

There is no SYSPRES pin in BQ34Z950, is there any alternative pin available in BQ34Z950 IC?

Observations:

1)When battery pack is connected 3 leds are ON for 14.8v and 4 leds ON for battery pack with 15.6v. If these indications are shown seems correct why IC does not switch ON DSG PIN?

2)These Indications goes away and a single LED is blinking (LED1) when I start communication with BQ34Z950. What does it signifies? 

3) When battery connected no voltage is observed on PACK pin. When charge voltage(16.8v) is applied DSG pin goes HIGH still there is no current flow to charge the battery.

4) When this applied voltage(16.8v) is removed DSG pin goes LOW again.

5) I am using 4S3P battery pack, sense resistor used now is 10mOhm.

Please detail me about EV2300 interface board and software for BQ34Z950.

Thanks,

Swapnil

Swapnil,

 You are correct that the device does not provide the SYSPRES feature. You should check the RSVD bit 3 in the Operation Cfg B register and set it to 1, if it is not already set. You will need a special bqEVSW program to use with the bq34z950 firmware and I will send you a link to download the setup file.

1) Are the VOK and QEN flags set in the Operation Status register? If not, then IT is not enabled.

2) I have not seen this before. The LEDs should only flash during charging.

3) and 4)  This is normal, if the DSG FET is not turned on.

Regards

Tom

Hello Thomas,

Will you please brief me about initial conditions for BQ34Z950. I have replace IC in my circuit but found no change in working of DSG pin. How to check whether IC has set its registers so that DSG PIN is pulled low or in circuit there is some condition that is causing this problem.

I have not made any communication with this replaced IC yet. Will you please guide me regarding circuit issue or any precautions needed to be taken.

Thanks and Regards

Swapnil Misal

Hello Thomas,

Thanks for your reply. I am waiting for EV2300 module to arrive at my place, as soon as I get that, will try setting CHG and DSG flags through software.

I have build circuit as it was given in datasheet revised may 2013. Only change is instead of Si4435DY (Q3) mosfet i have used FDS4435 mosfet. PMS pin connected to ground through 100k resistor and only ZVCHG pin connected to gate terminal of Q3 through 5.1K resistor.

And instead of thermistor i used fixed 10k resistor. Will you please let me know the calculation and input range of TS1 (temperature sense pin) for proper operation of BQ34Z950 without temperature failure detection.

I also want you to explain about ASRP , ASRN, GSRp, GSRN pin states and input range for proper operation.

Thanks and Regards,

Swapnil Misal

Swapnil,

I will review your schematic, if you can send it.

You can probably get by without calibrating the temperature sensor, since you are not using a thermistor. The resistance value of the resistor should not change much over temperature.

The ASRP and ASRN pins are the current sense inputs for the hardware based current protection features. They are not filtered and can respond much faster than the coulomb counting interface. The GSRP and GSRN pins are the current sense inputs for the firmware based current sense features. This includes coulomb counting and firmware controlled current protection.

Tom

1072.SCHEMATIC1 _ 3_Li-Ion_Battery_P.pdf

Hello Thomas

I have inserted schematic file. Three things i could not understand in datasheet schematic is use of Q5(BSS138) which I replaced with NDS7002A , use of diodes at BAT and PACK input pins of IC BQ34z950 and use of two 0.1uF capacitors across 4p and PACK+.

Please let me know if any thing has gone wrong.

Thanks and Regards

Swapnil Misal

7673.SCHEMATIC1st_Li-Ion_Battery_P.pdf

Hello Thomas

I have also tried above schematic but found same issue.

And I also want to ask, how to define Over Temperature during Discharge and Charge state? How to check whether IC BQ34Z950 is in OTC or OTD mode? What range of voltage should be at TS1 pin?

Are there any test points that can suggests the circuit built is functioning correct?

Thanks and Regards

Swapnil Misal

Hello Thomas,

I will receive EV2400 module. Can you please mail me software required for it.

Thanks and regards

Swapnil Misal

Swapnil,

The EV2400 drivers are available for download from the product website.

Tom

Hello Thomas

I got started with my circuit. Using EV2400 board and software you sent me I forcible enabled both (CHG, DSG) MOSFETS.

Now I can observe 16v at Pack+ terminal. Thanks for your help.

But want to know weather on short circuit will DSG MOSFET get OFF ? I have attached EVM software snapshot, what more setting are required to be done or what flags need to be set?

Thanks and Regards

Swapnil Misal

Hello Thomas,

Having some issue with Over Current charge and Discharge Recovery.

I set OC (1st Tier) Dsg = 600mA and load of 1A was connected. Discharging mosfet was switched OFF.But would not recover it back from this condition, flags do not get reset.

If i manually reset BQ34Z950, everything starts fine.

Same problem was observed for charging over current recovery. Please guide me with this Issue.

Thanks and Regards

Swapnil Misal

Hey can anyone reply to this query please.

Swapnil,

I checked it on the bench and the device recovered from OCD and OCC faults. You could try reloading the default senc file or you can extract your senc file and send it to me to test.

Tom

Hello Thomas,

I am getting these error messages when trying to read file from flash memory option in tool bar.

So I am not able to create .senc file which you expected from me.

Can you suggest what next thing i need to do.

Thanks and Regards

Swapnil Misal

Swapnil,

You could see these error messages if your device is in Sealed mode or if the FW is not compatible with the bqEVSW. The FAS and SS flags were green in a previous message adn this would indicate that the pack us not sealed. Please confirm that they are still green in the Operation Status register on the SBS screen. I believe that I provided the bqEVSW setup program to you, but maybe you do not have the correct firmware. I attached the production firmware to this message. You should be able to load it.

Tom

Hello Thomas, 

I loaded the firmware file as you suggested. Will you please guide me for what the next steps to be taken in order to complete all settings and calibration process in BQ34Z950.

Just after loading firmware file, I again tried to read .senc file but same error occurred.

Please tell what are the next steps to be performed.

And it takes 2 sec to detect short circuit condition is that right ?

Let me know about alarm conditions and LED indication relation.

Thanks and Regards

Swapnil 

Dear Tom,

I am very glad to know that there is a version which can talk with BQ34Z950. We have got few samples for our customer from TI and they just ask me for software to use with EV2300. Can you send link to me also?

Thank you very much in advance fo r your support!

Michail, 

Please provide an email address and I can send  link to download the setup program. 

Tom

Dear Tom,

my email : mike at taksom dot com

thank you!

Dear Thomas,

we are trying to use bq34z950 with 3 cell LiOn battery pack (3x3.9V, 5A). We connect it to the pc with EV2300. After making some correction to the default settings IC did not want to change or return to default internal flash (if we put new data to any field it became red after pressing enter).IC still answer to requests, update status and information, we can run calibration. Before this happen we has problem with normal working mode (discharge) - IC did not turn on FET (but pin and mosfet work - we saw it making calibrating). May be you can take a look to the attached files and help us to find our mistakes?

Mike

7610.ic_data.zip

Michail,

The device has  a PF fault, which will prevent data flash updates. Try using the Write 2 word Command button and send the PF clear command. 2673 1712

Tom

Dear Tom,

Thank you very much for your help!

Michail