Other Parts Discussed in Thread: DRV8711
Tool/software:
Hi TI Team,
We are currently developing a Battery Management System (BMS) product using the BQ76940 IC, interfaced with an STM32 microcontroller. Our objective is to read and control key parameters such as cell voltages, pack current, pack voltage, and temperature. We have successfully read the individual cell voltages and pack voltage.
Queries:
1.However, when attempting to read the pack current registers (0x32, 0x33, Coulomb counter), we are consistently receiving invalid (junk) values 0x0042.
2.We also attempted to enable the CHG and DSG bits in the SYS_CTRL2 register. However, the charge and discharge functions did not operate as expected. Furthermore, after writing to the register (0x41, 0x42), it always reads back as 0x00.
3.Additionally, we tried configuring the UV and OV thresholds, but upon reading the respective registers, they return only the default values specified in the datasheet. Despite this, every write operation has returned HAL_OK status from the STM32 HAL library.
Example: Write register value 0xC7(4.2V) -OV, 0x4E (2V)-UV -For testing.
When we read 0xAC -OV, 0x97 -UV (default value).
4.The NTC thermistor register read and temperature calculation are functional, but the measured values differ from the actual temperature, and further verification is required.
5.In addition, we have also enabled the cell balancing function. We would like to seek clarification on the cell balancing method implemented in the BQ76940 IC. Specifically, we request details on how the balancing process is carried out between the cells, and under what conditions the IC activates and manages the balancing operation.
We urgently need to resolve these issues and achieve accurate parameter readings. Multiple approaches have been tried without success, and we are running behind schedule for product delivery to our customer.
We kindly request your guidance and support in resolving these queries at the earliest possible time.
Thank you in Advance.
