SLUAB06 January   2025 AMC131M02 , AMC3330 , ISO7731

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Topologies for Insulation Monitoring in ESS
    1. 2.1 Single Switch Topology
      1. 2.1.1 Test Steps
    2. 2.2 Dual Switch Floating Sampling Topology
      1. 2.2.1 Test Steps
    3. 2.3 Dual Switch Sampling in High Voltage Side Topology
    4. 2.4 AC Injection Topology
  6. 3Comparison of Designs
    1. 3.1 Injection Resistance Influence on Accuracy
  7. 4Capacitor Influence on Sampling Time
    1. 4.1 How to Choose Y Capacitor
    2. 4.2 Sampling Time
  8. 5Key Devices
    1. 5.1 BQ79731-Q1
    2. 5.2 UCC33421-Q1
    3. 5.3 AMC131M02
    4. 5.4 AMC3330
    5. 5.5 ISO773x
  9. 6Topos Simulation Result and Conclusion
  10. 7Summary
  11. 8References

BQ79731-Q1

The BQ79731-Q1 can be used to measure divided down high voltage nodes in a battery system. It can measure voltage across Fuse, Contactors and check isolation voltage in a battery junction box (BJB) system. The device has two integrated current sense (BQ79731-Q1) paths supporting low-side shunt resistor. Coulomb counting (BQ79731-Q1) function is available for accurate SOC calculation. There are 15 GPIOs or auxiliary inputs that can be used for HV measurements, thermistor measurements, and driving relays. There are four SW outputs that can be used to drive MOSFET switches in the measurement path. The device can function as a SPI HUB and interface with up to eight separate SPI devices or groups. Over current protection response can be achieved autonomously using HW pins for fast protection in dangerous over current events. The isolated bi-directional daisy chain ports support both capacitor and transformer based isolation. The device can also communicate with MCU over SPI and UART.

 BQ79731-Q1 Functional Block
                    Diagram Figure 5-1 BQ79731-Q1 Functional Block Diagram