BQ76952EVM: Problem in pcb

chwayet fadi

Part Number: BQ76952EVM
Other Parts Discussed in Thread: BQ76952, BQSTUDIO,

Tool/software:

I have a BQ76952 EVM. There is an issue where the BQ is not working properly. When I measure the SCL, it provides 3.33V, but the SDA voltage fluctuates between 1.8V and 2.6V. Additionally, the REG18 provides 1.8V. This is happening on two board.

over 1 year ago

0 Thomas Rainey over 1 year ago

TI__Expert 4320 points

Hello,

Can you send the .gg file and what your EVM configuration is?

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

I am using STM32 code to communicate with the BQ76952 EVM and I suspect there is a hardware problem. Initially, when I measured REG18, it was 0V. After replacing the BQ IC, REG18 now delivers 1.8V. However, BQ Studio cannot detect the BQ EVM; the address 0x17 briefly appears and then disappears.

0 chwayet fadi over 1 year ago in reply to chwayet fadi

Prodigy 20 points

In BQ Studio, the I2C address appears momentarily and then disappears repeatedly.

0 Thomas Rainey over 1 year ago in reply to chwayet fadi

TI__Expert 4320 points

Hello,

Have you tried following the steps outline in this E2E?

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1082090/faq-bq76952evm-why-is-my-bq769x2-device-unable-to-connect-with-bqstudio

That should help solve your detection issue.

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

This is not helping. REG18 provides between 1.8V and 2.6V, the same voltage I measure on the SDA (while SCL measures 3.3V). This problem is common on both boards. On the first board, I know I applied a load higher than 6A, but the second board is also damaged despite having no load. If you can help me fix one board, I think I can fix the other

0 Thomas Rainey over 1 year ago in reply to chwayet fadi

TI__Expert 4320 points

Hi Chwayet,

REG18 voltage being higher than the absolute max sounds like the IC is damaged.

What what were you testing when you started to notice this behavior?

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

I am testing the RST_SHUTDOWN mode and the protection/permanent fail features

0 Thomas Rainey over 1 year ago in reply to chwayet fadi

TI__Expert 4320 points

A few questions:

1. Can you send a picture of the board and your configuration?

2. Can you list your testing with as much detail as possible?

3. Did both boards fail during this test?

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

For the first board, I know the issue is that I connected it to a load higher than 6A. I'm seeking a solution for this problem. On the second board, there is no charger or load, and the problem is unknown to me. However, the common factor between both boards is that REG1 and SDA voltages fluctuate between 1.8V and 2.6V. We need to find a solution to this problem. We cannot afford to keep buying boards at $250 a piece. Can TI replace the last board for us? I hope we do not stop the design using this chip, and look for alternatives, because of the evaluation board.

0 Thomas Rainey over 1 year ago in reply to chwayet fadi

TI__Expert 4320 points

Hello Chwayet,

If you provide the information listed above I can try and figure out the issue at hand.

For replacing the board you can refer to https://www.ti.com/support-quality/additional-information/customer-returns.html for help.

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

0 chwayet fadi over 1 year ago in reply to chwayet fadi

Prodigy 20 points

I enabled the FETs and activated the overvoltage (OV), undervoltage (UV), over-temperature (OT), and under-temperature (UT) protections. However, I did not implement current protection and used a load exceeding 6A. Additionally, I activated DFETOFF and cell balancing.

0 Thomas Rainey over 1 year ago in reply to chwayet fadi

TI__Expert 4320 points

Hello,

For the board that did not have a 6A load, what were the test procedures that you conducted in as much detail as possible? For example, if you were testing over voltage what specifically did you do to cause an over voltage.

I am trying to establish when the board started having these issues.

Best regards,

Thomas Rainey

0 chwayet fadi over 1 year ago in reply to Thomas Rainey

Prodigy 20 points

I use a generator to deliver voltage and set up cell simulator shunts. I implement the overvoltage condition such that when the voltage reaches 3650 mV, the FETs are deactivated.

For testing overtemperature, I use a 10k thermistor connected to CFETOFF. To simulate the condition, I bring a heat source (such as a small fire) near the thermistor. This setup is used to test the protection mechanism by deactivating the charge and discharge FETs.

I also activate the permanent fail feature(voltage reaches 4200mv), which causes the system to enter shutdown mode. After configuring the system, I connect the RST_SHUT pin to a GPIO pin to test the shutdown mode. When I connect the RST_SHUT to GPIO, the system turns off, and when I disconnect it, the system turns back on.