BQ78pl114

Hi Gareth,

Responses to your questions:

Question 1:

We do not advice that you calibrate the A/D. This is calibrated from the factory and stored in the part.  No additional calibration is required from the user.

Question2:

Calibartion is perfromed at the factory and stored in the part. No Calibration is needed by user.

Please refere to Chapter 8 of the TRM (http://focus.ti.com/lit/ug/sluu481/sluu481.pdf)

Question 3:

D-FET, C-FET and P-FET describe the status of the Dischage FET, Charge FET and the Precharge FET. It is the output from the FET Status Register

Refere to Page 91 of the TRM

Question 4:

To change the SMBus Address you will have to use the bqWizard.

(bqWizard >> Utilities >> SMBus Address)

Question 5:

To claer a fault:

    1) Remove the condistion that is causing the fault

    2) You can then  reset the fuse by using the Reset Fuse Command in the bqWizard (bqWizard >> Commands >> Reset Fuse)

Hope this is helpful.

Regards,

Ben

Ben,

With all due respect, I have a set of BQ78PL114S12, V5000 firmware, that is out of calibration.  They read 0.200V high compared to the reference voltage.  The 4 BQ78pl102's that we use are perfectly fine.  You can see the jump in values when we do transfer function.  The problem is my over-voltage protection trips early when charging.  For now we've set the OV trip limit to 4.45.

We do need an answer to Question 1.  How about:  Does it or not?  Does the software response "Succeeded" when cailbrating voltage a joke when the read value stay the same?   If we can calibrate, how about the secret to calibrate?

Regards,

Randy

Hi Gareth,

Could you provide a screen capature of the bqWizard Screen. Also could you diescribe more the failure you are seeing.

Also, to understand the fault that might be occuring, you might want look at that Safety History

Ben

Hi Randy,

I understand your questions now.

On the BQ78PL114S12, with F/W V5000 you are able to calibrate  the A/D for cell voltages on the PL114.

The Calibration values for Cells 5-12 have the factory values coded on-board the 102 IC and hence if you do a Relearn / Initialize, the Factory Values will overwrite the Calibration Values you entered.

So in summary, Calibration of Cell Voltages on the PL114 will only change the values for the first 4 cells.  

Note: With F/W V6000 of the F/W (Conversion to bq78PL116) locks out the calibration capability on the PL116.

Calibration is outlined in TRM (Chapter 6)

(http://focus.ti.com/lit/ug/sluu330b/sluu330b.pdf

Regards,

Ben

Ben,

I found my answer.

My original problem is that I discovered that all my voltage calibrations on the 114 chips were 0.200V too high.  I didn't notice it until I did a relearn.  All the 102 chips voltages shifted 0.2V lower and contrasted the error.  voltage measument of the cell confirmed that the 102 chips were correct and all the 114 chips were off.

My solution was to recalibrate the 4 voltages on the114, but, it would not calibrate.  The temp and current zero and slope values calibrated, but, cell voltages wouldn't.

After a full day of experimenting with the cal process, I came to realize you had to methodically follow only one path to calibrating voltages.  That is, to calibrate each cell, first zero point cal and then span point cal and then move on to the next one.  I was doing all zero points and then all span.   This is the trick.  You can't do all the zero's and spans seperately or a just span by itself to tweak the upper end. 

The problem with this is that I have all my cells already soldered on a flex circuit and I would have to fully charge or discharge a 50V pack, 5Ah pack 8 times while I was still in the charge mode for 20 packs.  Or unsolder all my cells.

Now I didn't expect to do all this because I was counting on the fact that this Voltage Cal was all done at the factory and didn't notice the cal was off until I relearned/transferred the cal info from the 102 chips.

What I've decided to do for now is save a "cal file" from a correctly calibrate board and load the cal file to my other assembled packs and re-transfer the 102 data back into the 114 chip.

Randy

Randy,

Great! you were able to resolve your issue.

On the PL116 (PL114 with the V6000 F/W) we have updated the F/W to manitain the voltage calibration data from the factory. This will not be overwritten with a relearn.

Ben

Hi Gareth,

If you have completed calibration, I will advice you retry the calibration.

Also, please ensure that the location of the temperature sensors are correctly identifies in the bqWizard.

Utilities>>AddOns >>PackConfigurations>>Tmap Configuration

You will have the option for the temperature sensor setup.

Hope this helps.

Ben