18 cells BMS with (LTC6813-1) and active balancer LTC3300-1 x3

Dear Friends,

We are planning to make 18 cells BMS with bidirectional active balancer. In order to that we are considering LTC6813-1 as 18 cell battery stack monitoring and LTC3300-1 x3 for link with active balancer. I have a few questions to clarify.

Q1 which is the best way to setup ISP communication with MCU?
     A) using two separate isolator with setup1 or single isolator with setup2
 
setup1           SETUP2


Q2 In the LTC3300-1 WDT protection circuit how to connect with cells and interface when using three cascade ICs? (DEMO CIRCUIT 2100 only use 2 chips ) could you please provide sample diagram for this

which cell need to connect, need sample interface circuit

Q3 We have seen LT2949 current Measurement Chip, in the BMS category front page, but unable to find this chip any detail ? (do you have any suggestion chip for 18cell current measurement chip (shunt resistor - 250A)

Thank you!

Parents
  • +1
    •  Analog Employees 
    on Aug 9, 2019 6:44 PM

    Concerning the setups:

    • Setup 1 is useful if you do not want to have the same power ground for the LTC6813 and bottom LTC3300.  For high current applications such as yours it is probably the best choice.
    • With careful system grounding it is OK to use setup 2.
    • Also possible ("Setup 3") is to communicate with the LTC3300-1's through the SPI-bus in the LTC6813.  With this approach, communication to LTC6813 is over isoSPI bus.  isoSPI bus can be driven from MCU using LTC6820 isoSPI converter.  This is similar to the approach for the DC2100B.

    For the protection circuits extension to 3 ea. LTC3300, see the attachment.PDF

    The LTC2949 is not a released product, so there is no public information available.

Reply
  • +1
    •  Analog Employees 
    on Aug 9, 2019 6:44 PM

    Concerning the setups:

    • Setup 1 is useful if you do not want to have the same power ground for the LTC6813 and bottom LTC3300.  For high current applications such as yours it is probably the best choice.
    • With careful system grounding it is OK to use setup 2.
    • Also possible ("Setup 3") is to communicate with the LTC3300-1's through the SPI-bus in the LTC6813.  With this approach, communication to LTC6813 is over isoSPI bus.  isoSPI bus can be driven from MCU using LTC6820 isoSPI converter.  This is similar to the approach for the DC2100B.

    For the protection circuits extension to 3 ea. LTC3300, see the attachment.PDF

    The LTC2949 is not a released product, so there is no public information available.

Children