TIDUF43 August   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Terminology
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS1213-Q1 45V, Low IQ, Automotive High-Side Switch Controller With Low-Power Mode and Adjustable Load Wakeup Trigger
      2. 2.3.2 INA296x-Q1 AEC-Q100, –5V to 110V, Bidirectional, 1.1MHz, 8V/μs, Ultra-Precise Current-Sense Amplifier
  9. 3System Design Theory
    1. 3.1 Low-Power Mode Considerations
    2. 3.2 Precharge Circuit Considerations
    3. 3.3 Short-Circuit Protection
    4. 3.4 LM74704-Q1 Enable
    5. 3.5 Headers
      1. 3.5.1 Headers for Configuring INA296B-Q1
      2. 3.5.2 Headers for Configuring TPS1213-Q1
    6. 3.6 Software Considerations
      1. 3.6.1 Fuse Channel Definition
      2. 3.6.2 Software Functions
    7. 3.7 Optional Output TVS Diode
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software
    3. 4.3 Test Setup
    4. 4.4 Test Results
      1. 4.4.1 State Transition
      2. 4.4.2 System IQ in Low-Power Mode
      3. 4.4.3 Precharge Test
      4. 4.4.4 Overcurrent Protection
      5. 4.4.5 PWM Overcurrent
      6. 4.4.6 Short-Circuit Protection
      7. 4.4.7 Thermal Testing
      8. 4.4.8 CISPR-25 Emissions Testing
        1. 4.4.8.1 Conducted Emissions Testing
        2. 4.4.8.2 Radiated Emissions Testing
        3. 4.4.8.3 Summary of Results
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 PCB Layout Recommendations
        1. 5.1.3.1 Layout Prints
      4. 5.1.4 Altium Project
      5. 5.1.5 Gerber Files
      6. 5.1.6 Assembly Drawings
    2. 5.2 Documentation Support
    3. 5.3 Support Resources
    4. 5.4 Trademarks
  12. 6About the Author

4.4.4 Overcurrent Protection

The test setup for verifying the software-based time-current characteristics involves a similar setup as seen in Figure 4-2, except the LM53625xQEVM is removed from the path. A 1000W electronic load is connected directly to the output of the TIDA-020065 and the load is configured in constant resistance mode.

For this test, fuse channel 3 is used, which means Inom = 25A and I2t = 1000A2s. When the load experiences a constant overcurrent of 36A, a shutdown time of 1.49s is expected. It takes 1.523s for the I2t algorithm to pulldown INP and shutdown the output.

TIDA-020065 Overcurrent Event (Inom = 25A, I2t = 1000A2s) Figure 4-9 Overcurrent Event (Inom = 25A, I2t = 1000A2s)

Figure 4-10 and Figure 4-11 both show results from I2t shutdown testing using fuse channel 1 and fuse channel 2, respectively.

TIDA-020065 I2t Tests for Fuse Channel 1 (Inom = 15A and I2t = 340A2s) Figure 4-10 I2t Tests for Fuse Channel 1 (Inom = 15A and I2t = 340A2s)
TIDA-020065 I2t Tests for Fuse Channel 2 (Inom = 20A and I2t = 520A2s) Figure 4-11 I2t Tests for Fuse Channel 2 (Inom = 20A and I2t = 520A2s)

In addition to fuse I2t behavior for overcurrents up to 65.5A, the fixed-delay shutdown behavior was also captured.

For this test, the fixed-delay threshold was set to 65.5A in software. As shown in Figure 4-12, the 65.5A pulse is close to the maximum monitorable current for this design, so the MSPM0L1306-Q1 asserts INP low when the pulse is active for 4ms to shutdown the output.

TIDA-020065 Fixed-Delay Shutdown Event Figure 4-12 Fixed-Delay Shutdown Event