STDA040 August   2026 BQ76907-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2E-latch System Architecture
  6. 3Typical Design
    1. 3.1 Motor Drivers
    2. 3.2 Network Connection
    3. 3.3 Microcontroller
    4. 3.4 Backup Power
      1. 3.4.1 Discussion of Energy Requirements
        1. 3.4.1.1 Energy Needed By A Single Motor
        2. 3.4.1.2 Requirements for Multiple Motors
        3. 3.4.1.3 Usable energy stored
        4. 3.4.1.4 Derating the Capacitance
      2. 3.4.2 Charging Circuit
      3. 3.4.3 Discharging Circuit
      4. 3.4.4 Bidirectional Charge and Discharge Circuits
      5. 3.4.5 Cell Balancing Circuit
    5. 3.5 Position Sensors
  7. 4Future Trends and Innovations
  8. 5Conclusion
  9. 6References

2 E-latch System Architecture

A typical E-latch system is made up of several components and can be arranged as either a centralized system or in a distributed manner. In a centralized system, a single module provides the backup power and optionally redundant drivers, which are required for operation of all the latches and locks throughout the vehicle. This arrangement is often called a crash protection module (CPM) or crash unlock protection module (CUPM). In a distributed system, the energy storage and drivers for each door are controlled and driven locally.

BQ76907-Q1 Distributed (Left) and Centralized (Right) E-latch Architectures Figure 2-1 Distributed (Left) and Centralized (Right) E-latch Architectures

There can also be hybrid arrangements, for example with each side of the vehicle having an E-latch system for the doors.