TIDUF61 May   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 TLV9002-Q1
      2. 2.2.2 TLV9034-Q1
      3. 2.2.3 TPS7B69-Q1
      4. 2.2.4 SN74HCS08-Q1
      5. 2.2.5 SN74HCS86-Q1
    3. 2.3 System Design Theory
      1. 2.3.1 TIDA-0020069 Operation
        1. 2.3.1.1 Constant Current Source
          1. 2.3.1.1.1 Design Goals
          2. 2.3.1.1.2 Design Description
          3. 2.3.1.1.3 Design Notes
          4. 2.3.1.1.4 Design Steps
        2. 2.3.1.2 Current Sensing
          1. 2.3.1.2.1 Design Goals
          2. 2.3.1.2.2 Design Description
          3. 2.3.1.2.3 Design Steps
        3. 2.3.1.3 Load Connections and Clamps
        4. 2.3.1.4 Modified Window Comparator
        5. 2.3.1.5 Digital Logic Gates
      2. 2.3.2 Status Indication
        1. 2.3.2.1 Normal Operation (Closed Connection) State
        2. 2.3.2.2 Open Connection State
        3. 2.3.2.3 Short-to-Battery State
        4. 2.3.2.4 Short-to-Ground State
  9. 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 Normal Operation (Closed Connection) Test Results
      2. 3.3.2 Open Connection Test Results
      3. 3.3.3 Short-to-Battery Test Results
      4. 3.3.4 Short-to-Ground Test Results
      5. 3.3.5 Disable (Shutdown) Test Results
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  11. 5Tools and Software
  12. 6Documentation Support
  13. 7Support Resources
  14. 8Trademarks
  15. 9About the Author

3.3.3 Short-to-Battery Test Results

Figure 3-9 shows the TIDA-020069 board configured in the short-to-battery failure state. In this state, the HVIL load has experienced a short to the 12V battery voltage at some point in the loop. This short can occur before, after, or between the load resistors. This replicates the failure mode within an HEV/EV, as the HVIL system cannot determine if the connectors are in a closed or open configuration during this short failure. This failure can also occur when the HVIL-Send and HVIL-Return pins are shorted together. In this scenario, current is still measured across the shunt resistor, but no current is flowing through the HVIL load resistors. This reference design accounts for this failure scenario.

The Short to Battery LED indicator is turned on in Figure 3-9, as expected for this state. This verifies the logical interpretation of the HVIL-Send and HVIL-Return voltages in this state.

TIDA-020069 Short-to-Battery Test Results Figure 3-9 Short-to-Battery Test Results