BQ34Z100-R2: Voltage Calibration

jeong hun lee

Prodigy 110 points

Part Number: BQ34Z100-R2
Other Parts Discussed in Thread: BQSTUDIO, EV2400

Tool/software:

I am using uC to control BQ34Z100-R2.

And I can read and write data via I2C communication.

I read the voltage value using command code 0x08, but it is not the value I want.

The power source currently in use is a lithium-ion battery pack 7S1P.

When I measure the voltage of the battery pack, it measures 25.95V.

When measuring the voltage of the battery pack, 25.95V is measured.
Therefore, the voltage value should be 25950.
However, as shown in the figure below, the voltage value is 14.

I found a similar case in the link below and tried it, but the result is different.

e2e.ti.com/.../bq34z100-r2-voltage-and-temperature-calibration-issues

I used R1 = 562K, R2 = 16.5K as distribution resistors.

- Battery Pack Voltage: 25.95V

- Use the external voltage divider (set the PackConfiguration[VOLSEL] bit)

Pack Config: 26977(Decimal value) -> 0x6961(Hexadecimal value)

If you read the Pack Config value using the extended command 0x3A, you can see that it is the same as the setting value.

Use the voltage divider 35060

This value is determined by the calculation below.

Vout = (Vs * R2) / (R1+R2)

1V = Vs * (R2 / (R1 + R2))

Vs = 1V * ((R1 + R2) / R2)

Vs = 1V * ((562K + 16.5K) / 16.5K)

Vs = 35.060V = 35060mV

If you look at the picture below, you can see the set Voltage Divider values.

And the number of cells is set to 1.

Is there something wrong with my setup?

1 month ago

0 Diego 1 month ago

TI__Mastermind 20580 points

Hi,

These resources may be helpful to you.

(+) BQ34Z100-R2: Voltage and temperature calibration issues - Power management forum - Power management - TI E2E support forums

Perform voltage calibration with the BQ34Z100-G1 | Video | TI.com

(+) [FAQ] BQ34Z100-G1: How to Calibrate Gauge at High Voltage - Power management forum - Power management - TI E2E support forums

(+) BQ34Z100-G1: Commands for calibration procedure - Power management forum - Power management - TI E2E support forums

Regards,

Diego

0 jeong hun lee 1 month ago in reply to Diego

Prodigy 110 points

hi Diego

thank you for your answer.

I tried all the answers but I still get different values.

Here's my procedure for calibrating voltage:

1. Connect the battery pack.

2. Put the MCU into debugging mode.

3. Convert bq34z100-r2 to UNSEALED mode.

4. Read the CONTROL_STATUS Flags to check if FAS=1, SS=0.

5. If there is no problem Set the [VOLTSET] bit of Pack Configuration to 1.

6. Write the newly calculated checksum value using the 0x60 command.

7. Set the value 35060 in Voltage Divider

8. Write the newly calculated checksum value using the 0x60 command.

9. Set the number of series cells to 1

10. Write the newly calculated checksum value using the 0x60 command.

11. Reset the bq34z100-r2 using command 0x0041.

12. Convert bq34z100-r2 to SEALED mode.

13. Read the Voltage() value using command 0x08.

Is there something wrong with the procedure I followed?

0 Diego 1 month ago in reply to jeong hun lee

TI__Mastermind 20580 points

Hi,

In your process, you did not send a CAL enable cmd, cc offset cmd, etc.

(+) BQ34Z100-G1: Commands for calibration procedure - Power management forum - Power management - TI E2E support forums

Regards,

Diego

0 jeong hun lee 1 month ago in reply to Diego

Prodigy 110 points

I corrected the CC OFFSET by sending CAL enable cmd and cc offset cmd as you answered.

The video above was shot in debugging mode.

In the video you can see the CCA bit being set and then cleared.

I think this has been corrected normally.

But the voltage value is still coming out differently.

I want to ask one thing.
Voltage() command code is 0x08, 0x09.

I want to know if I should read 2 bytes consecutively from command code 0x08 or 1 byte from command code 0x08 and 1 byte from command code 0x09.
The way I am currently using it is reading 2 bytes consecutively from command code 0x08.

0 Diego 1 month ago in reply to jeong hun lee

TI__Mastermind 20580 points

Hi,

Can you use BQstudio to calibrate this device?

This documentation will help. Gauge Communication

Regards,

Diego

0 jeong hun lee 1 month ago in reply to Diego

Prodigy 110 points

Hi,

I can't use BQstudio.

Because there is no EV2400.

I created a program by referring to the Gauge Communication that was shared.

Is there anything I can't do without BQstudio?

0 Diego 1 month ago in reply to jeong hun lee

TI__Mastermind 20580 points

Hi,

The EV2400 + BQstudio are needed for programming the ChemID and generating bq.fs and .srec files. Everything else can be configured using an MCU.

Regards,

Diego

0 jeong hun lee 1 month ago in reply to Diego

Prodigy 110 points

Hi, Diego

Thank you for answering my question.

Is programming ChemID and generating bq.fs and .srec files only possible with BQstudio?

Is the only way to do the initial setup in BQstudio, then after the setup is complete, create the bq.fs and .srec files and upload them to the BQ34Z100-R2 using BQstudio?

Otherwise, if I have a bq.fs or .srec file with the settings completed, can I set the settings of BQ34Z100-R2 via MCU?

If possible, what are the methods and procedures?

0 jeong hun lee 29 days ago in reply to Diego

Prodigy 110 points

Hi Diego
I solved this problem by simply changing the write order.
At first, I set the VOLTSEL bit in Configuration->Registers->Pack Configuration of Data flash to 1, set the Number of series cell to 7, and then set Calibration->Data->Voltage Divider of Data flash to 5008.
This resulted in the voltage being 65535.
I changed the order and set Calibration->Data->Voltage Divider of Data flash first, and then set Configuration->Registers of Data flash, and confirmed that the voltage was read normally.
Thank you for your help.