MC33771 S32K BALANCING

[sushma]

Hello.

The following observation was made when the balancing was enabled, although balancing of one cell is activated, other cells also seem to discharge; two approaches were followed :

1) BCC_SetCBIndividually(bccDrvConfig, 1, 13, true); - balances the 14 cell
Results : 3391 3391 3374 3384 3415 3405 3314 3322 3428 3429 3430 3390 3431 3431

3378 3376 3360 3370 3406 3396 3297 3307 3423 3424 3423 3374 3427 3421
But other than the 14th cell, even other cell seems to be dissipated.

Register values :
----------------------------------
| Register | Value |
----------------------------------
| drv_status | 0x0001 |
| INIT | 0x0001 |
| SYS CFG1 | 0x5380 |
| SYS CFG2 | 0x0DA1 |
| SYS DIAG | 0x0000 |
| ADC CFG | 0xA716 |
| ADC2 OFFSET COMP | 0x8000 |
| OV UV EN | 0xFFFF |
| CB1 CFG | 0x00FF |
| CB2 CFG | 0x00FF |
| CB3 CFG | 0x00FF |
| CB4 CFG | 0x00FF |
| CB5 CFG | 0x00FF |
| CB6 CFG | 0x00FF |
| CB7 CFG | 0x00FF |
| CB8 CFG | 0x00FF |
| CB9 CFG | 0x00FF |
| CB10 CFG | 0x00FF |
| CB11 CFG | 0x00FF |
| CB12 CFG | 0x00FF |
| CB13 CFG | 0x00FF |
| CB14 CFG | 0x02FF |

2) BCC_SetCBIndividually(bccDrvConfig, 1, 0, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 1, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 2, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 3, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 4, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 5, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 6, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 7, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 8, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 9, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 10, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 11, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 12, false);
BCC_SetCBIndividually(bccDrvConfig, 1, 13, true);
Only the 14th cell balancing was enabled, rest all were disabled.

Results :
3375 3374 3357 3367 3403 3392 3292 3302 3421 3425 3423 3372 3426 3420

3367 3367 3349 3360 3401 3389 3282 3291 3420 3425 3421 3361 3423 3414
But other than the 14th cell, even other cell seems to be dissipated.

Register values :
----------------------------------
| Register | Value |
----------------------------------
| drv_status | 0x0001 |
| INIT | 0x0001 |
| SYS CFG1 | 0x5380 |
| SYS CFG2 | 0x0DA1 |
| SYS DIAG | 0x0000 |
| ADC CFG | 0x5716 |
| ADC2 OFFSET COMP | 0x8000 |
| OV UV EN | 0xFFFF |
| CB1 CFG | 0x00FF |
| CB2 CFG | 0x00FF |
| CB3 CFG | 0x00FF |
| CB4 CFG | 0x00FF |
| CB5 CFG | 0x00FF |
| CB6 CFG | 0x00FF |
| CB7 CFG | 0x00FF |
| CB8 CFG | 0x00FF |
| CB9 CFG | 0x00FF |
| CB10 CFG | 0x00FF |
| CB11 CFG | 0x00FF |
| CB12 CFG | 0x00FF |
| CB13 CFG | 0x00FF |
| CB14 CFG | 0x02FF |

Kindly look into this issue and suggest a solution.

Thank you.

[TomasVaverka]

Hi Sushma,

We have performed some measurements on our EVB and it seems that the function BCC_SetCBIndividually is working properly. Which status does this function return in your case and what is the value of the CB_DRV_STS register which shows the actual state of the cell balance drivers?

Best regards,

Tomas

[sushma]

Hello Thomas,

I have used the function and checked the status DRV_STATUS and CBx_CFG to confirm if the cells are balancing.

 I have enabled the function in monitoring.c file as BCC_SetCBIndividually(bccDrvConfig, 1, 9 or 14 (*tried two examples*), true); .

My question is : When only one cell balancing is enabled,I see all other cells also dissipating along with it. Why is it so?

----------------------------------
| Register | Value |
----------------------------------
| drv_status | 0x2000 |
| INIT | 0x0001 |
| SYS CFG1 | 0x5380 |
| SYS CFG2 | 0x0DA1 |
| SYS DIAG | 0x0000 |
| ADC CFG | 0x8716 |
| ADC2 OFFSET COMP | 0x8000 |
| OV UV EN | 0xFFFF |
| CB1 CFG | 0x00FF |
| CB2 CFG | 0x00FF |
| CB3 CFG | 0x00FF |
| CB4 CFG | 0x00FF |
| CB5 CFG | 0x00FF |
| CB6 CFG | 0x00FF |
| CB7 CFG | 0x00FF |
| CB8 CFG | 0x00FF |
| CB9 CFG | 0x00FF |
| CB10 CFG | 0x00FF |
| CB11 CFG | 0x00FF |
| CB12 CFG | 0x00FF |
| CB13 CFG | 0x00FF |
| CB14 CFG | 0x02FF |

 .

RESULTS : (when balancing of 14th cell was enabled)

3255 3240 3212 3232 3308 3279 3065 3096 3366 3383 3367 3208 3360 3350 - INITIAL 
3246 3232 3199 3221 3299 3269 3047 3077 3363 3378 3363 3198 3357 3331 - FINAL 
9          8       13      11      9      10    18    19       3       5       4       10       3    19  _difference in voltages

  ----------------------------------
| Register | Value |
----------------------------------
| drv_status | 0x0200 |
| INIT | 0x0001 |
| SYS CFG1 | 0x5380 |
| SYS CFG2 | 0x0DA1 |
| SYS DIAG | 0x0000 |
| ADC CFG | 0x7716 |
| ADC2 OFFSET COMP | 0x8000 |
| OV UV EN | 0xFFFF |
| CB1 CFG | 0x00FF |
| CB2 CFG | 0x00FF |
| CB3 CFG | 0x00FF |
| CB4 CFG | 0x00FF |
| CB5 CFG | 0x00FF |
| CB6 CFG | 0x00FF |
| CB7 CFG | 0x00FF |
| CB8 CFG | 0x00FF |
| CB9 CFG | 0x00FF |
| CB10 CFG | 0x02FF |
| CB11 CFG | 0x00FF |
| CB12 CFG | 0x00FF |
| CB13 CFG | 0x00FF |
| CB14 CFG | 0x00FF |.

RESULTS : (when balancing of 10th cell was enabled)

3241 3224 3190 3213 3295 3263 3024 3059 3357 3363 3358 3187 3351 3324- INITIAL 
3223 3203 3168 3191 3279 3247 2976 3019 3346 3327 3348 3163 3341 3314 - FINAL 
18       21       22      22    16    16    48    40       11    36       10       24    10    10 _difference in voltages

[TomasVaverka]

Hi Sushma,

It does not seem to be a software issue, most likely it is a hardware problem. I have asked my colleagues to get some insight on this and will get back to you as soon as possible.

Thank you for your patience.

Best regards,

Tomas

[TomasVaverka]

Hi Sushma,

Could you please elaborate on your hardware setup?

What kind of cells/battery are you using and are you sure there is no load connected to the battery?

What are the results when the balancing is disabled?

Best regards,

Tomas