TIDUEB2A July   2022  – July 2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1  Power Multiplexing Circuit Design Parameters
      2. 2.2.2  Input Connections and Filter
      3. 2.2.3  Reverse Polarity Protection
      4. 2.2.4  Battery Charger Input
      5. 2.2.5  Battery Ideal Diode-OR
      6. 2.2.6  Input and Battery Switchover Mechanics
      7. 2.2.7  LM74800 (U1) HGATE
      8. 2.2.8  Battery LM74800 HGATE
      9. 2.2.9  BQ25731 Design Considerations
      10. 2.2.10 BQ25731 Component Selection
      11. 2.2.11 ILIM Circuit
      12. 2.2.12 MCU and I2C Bus Design Considerations
      13. 2.2.13 MSP430FR2475
      14. 2.2.14 I2C Bus Overview
      15. 2.2.15 MSP430 Connectors
      16. 2.2.16 MSP430 Power Supply
      17. 2.2.17 Sensing Circuits
      18. 2.2.18 Current Sensing
      19. 2.2.19 Voltage Sensing
      20. 2.2.20 Input Comparators
      21. 2.2.21 Software Flow Chart
    3. 2.3 Highlighted Products
      1. 2.3.1 BQ25731
      2. 2.3.2 LM7480-Q1
      3. 2.3.3 LM74700-Q1
      4. 2.3.4 MSP430FR2475
      5. 2.3.5 PCA9546A
  8. 3Hardware, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Adaptive Charge Current Limiting
      2. 3.3.2 Battery ORing System
      3. 3.3.3 Circuit Switchover From Adapter to Battery
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  10. 5Revision History

2.3.3 LM74700-Q1

The LM74700-Q1 is an automotive AEC Q100 qualified ideal diode controller which operates in conjunction with an external N-channel MOSFET as an ideal diode rectifier for low-loss reverse polarity protection with a 20-mV forward voltage drop. The wide supply input range of 3.2 V to 65 V allows control of many popular DC bus voltages such as 12-V and 24-V battery systems. The device controls the GATE of the MOSFET to regulate the forward voltage drop at 20 mV. The regulation scheme enables graceful turn off of the MOSFET during a reverse current event and ensures zero DC reverse current flow. Fast response (< 0.75 µs) to Reverse Current Blocking makes the device suitable for systems with output voltage holdup requirements during ISO7637 pulse testing as well as power fail and input micro-short conditions.