TIDUF55 November   2023

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Power Tree and Wakeup
      2. 2.2.2 Insulation Requirement for Isolated Interface
      3. 2.2.3 Robust Relay Driver
      4. 2.2.4 Stackable Daisy Chain Communication
    3. 2.3 Highlighted Products
      1. 2.3.1  TMDSCNCD263
      2. 2.3.2  LMR51440
      3. 2.3.3  TPS7A16
      4. 2.3.4  TPS7B81
      5. 2.3.5  TPS62913
      6. 2.3.6  TPS4H160-Q1
      7. 2.3.7  ULN2803C
      8. 2.3.8  ISO1042
      9. 2.3.9  UCC12050
      10. 2.3.10 ISO1410
      11. 2.3.11 SN6505B
      12. 2.3.12 BQ32002
      13. 2.3.13 HDC3020
      14. 2.3.14 TPS3823
      15. 2.3.15 DP83826E
      16. 2.3.16 TPS763
      17. 2.3.17 LM74701-Q1
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Power Supply Testing
      2. 3.4.2 Daisy Chain Signal Quality
      3. 3.4.3 Relay Driving
      4. 3.4.4 Isolated CAN Transceiver Operation
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.1 Block Diagram

Figure 3-17 shows the system diagram.

GUID-20231019-SS0I-0CFP-LPW0-ZPTNQNC7GMWP-low.svg Figure 2-1 TIDA-010271 Block Diagram

The design uses the TMDSCNCD263 as a general-purpose MCU to operate and test all the functions including the power rail monitor, wakeup, relay switch, watchdog (WTD), real-time clock (RTC), humidity sensor, isolated CAN, isolated RS-485, Ethernet, and daisy chain communication.

The design uses the LMR51440 buck converter to convert the 24-V to 5-V power rail to supply the TMDSCNCD263, isolated power module UCC12050, and transformer driver SN6505B with a maximum 4-A capacity. A wakeup trigger circuit is designed to enable the LMR51440 from shutdown mode. The BQ79600 is supplied from TPS7A1601 in 12 V to support the reverse wakeup. The TPS7B8813 is used to convert the 5-V to 3.3-V power rail for VIO and power supply of peripheral devices.

The design uses an I2C bus to connect peripheral devices including humidity sensor, RTC and optional isolated high-voltage ADC or current ADC. The HDC3020 is used to measure the humidity to assess the possibility of dew formation in an IP67 BESS container. The BQ32002 backed up with a coin cell battery is used to generate a local time to the MCU.

Basic insulation is required for CAN and RS-485. The UCC12050 and ISO1042 devices are used to implement the isolated CAN communication function. The SN6505B and ISO1410 devices are used to implement the isolated RS-485 communication function. The ISO1410 can support up to 500Kbps data rates.

The design uses TPS3823-33 for timing supervision with a watchdog time out of 1.6 s.