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

3.4.2 Daisy Chain Signal Quality

This design uses a BMU (TIDA-010271) to communicate with BCU. The test point is in the BCU COMH port of BQ79600_0. The oscilloscope measures the COMP-COMN to check the positive pulse width, negative pulse width, rise slew rate, and fall slew rate.

Figure 3-17 through Figure 3-8 show the daisy chain waveforms.

GUID-20231019-SS0I-NPJ0-RJWM-WSGWHFMFXRCN-low.png Figure 3-5 Positive Pulse-Width of Daisy Chain
GUID-20231019-SS0I-3GFH-KFBV-KCFF1Z7WLWSH-low.png Figure 3-6 Negative Pulse-Width of Daisy Chain
GUID-20231019-SS0I-Q8K0-FCCV-F0KSCJ3LLNJC-low.png Figure 3-7 Raise Slew-Rate of Daisy Chain
GUID-20231019-SS0I-GZ6J-GXCG-VZXG658H6KSW-low.png Figure 3-8 Fall Slew-Rate of Daisy Chain

Table 3-18 lists daisy chain signal performance data.

Table 3-18 Daisy Chain Signal Performance
PARAMETER CONDITION MIN TEST DATA MAX
Positive pulse width Measure COMP-COMN from +1.8 V of rising edge to –1.8 V of next falling edge 230 ns 260 ns 270 ns
Negative pulse width Measure COMP-COMN from –1.8 V of falling edge to +1.8 V of next rising edge 230 ns 236 ns 270 ns
Rise slew rate Measure COMP-COMN from –1.8 V to +1.8 V of rising edge 50 ns
Fall slew rate Measure COMP-COMN from +1.8 V to –1.8 V of falling edge 39 ns