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BQ78350-R1A: Stand alone capability and compatibility with other AFEs

Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQ76920, BQ76952, BQ76930, BQ76940, BQ78350, BQ34110, EV2400, BQSTUDIO, BQ76952EVM, TIDA-010030

Hi

I am designing a BMS and intend to use the IC BQ78350-R1A, already a very comprehensive technical reference has been provided and it helps a lot.

But, I have some questions regarding BQ78350-R1A and are as follows:

1. It is mentioned in the datasheet that they are compatible with AFE ICs like BQ76920,76930 and 76940, I want to know that are they compatible with other AFE ICs as well for example BQ76952.

2. It is mentioned in the datasheet that it is compatible with a battery pack with a capacity of 320000 mAh, but the companion AFEs are not compatible for that high current, please suggest a suitable AFE for realizing that capacity.

Thank You

  • Hi Prabhat,

    The BQ78350-R1A can only be used with the BQ76920/BQ76930/BQ76940 companion AFEs. It was designed specifically to control this family of devices. The AFEs do not measure current directly, they measure the voltage across a sense resistor. So the sense resistor can be sized so that the full ADC range (+/-200mV) is used - you should also consider the SCD and OCD protection voltage limits when selecting the sense resistor size.

    If you would like to use the new BQ76952 AFE, you can consider using the BQ34110 top-of-stack gauge (if you need the gauging feature). It is similar to the BQ78350, but it uses the total stack voltage for gauging. You can refer to https://www.ti.com/tool/TIDA-010030 for an example of how to use a top-of-stack gauge with a battery monitor.

    Best regards,

    Matt

  • How to communicate with the gauge BQ78350-R1A without EVM2400.?

  • Hi Prabhat,

    You can communicate with this gauge using an MCU. You can chose which MCU you want to use - it will interface to the SMBus pins of the BQ78350-R1A. You will need to write your own MCU code using the BQ78350-R1A Technical Reference Manual which describes each of the registers and commands. 

    If you need the BQStudio software to run, you will need to use the EV2400. If the EV2400 is too expensive, we do have the board files available here if you want to build your own or include the circuit on your hardware: https://www.ti.com/tool/EV2400  For example, we include the EV2400 circuit on some of our device EVMs (like the BQ76952EVM) so that users do not need to purchase a separate EV2400 module.

    Best regards,

    Matt

  • I am currently prototyping a BMS with a custom and simple GUI for changing  BMS settings like battery chemistry, number of cells, charge rate, balancing current etc. Together with display of SOC, SOH and history of discharge although BQ Studio provides this function the GUI that I am working on is to make the BMS very simple to use and similar to available commercial systems.

    Is it possible to use BQ78350-R1A (together with BQ76940) to directly communicate with a PC for interacting with GUI.

    Currently based on support provided by you and my understanding that BQ78350*-R1A only provides SM BUS interface and I must include EV2400 in my BMS hardware.Pleasetell me if I understand things correctly.

    Regarding GUI (PC to BMS Communication)  do you have any support material?

    Based on review of TIDA-010030 It doesn't have any SMBus, but it is compatible with BQStudio, For this do we still need EV2400 and if I was to use this design would I need to include EV2400 in my BMS???

  • Hi Prabhat,

    Yes, you need the EV2400 to work with BQStudio. BQStudio is an evaluation tool and is not normally a requirement for a final system - normally there will be a host controller. BQStudio is the only GUI we offer.

    For TIDA-010030, an EV2400 was used to perform some of the system testing.

    Best regards,

    Matt