TIDUF09 December   2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Theory of Operation
    4. 2.4 Highlighted Products
      1. 2.4.1 TPS7A57 Low Dropout (LDO) Regulator
      2. 2.4.2 LMG1020 Low Side Driver
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
      1. 3.2.1 Optional Load Transient Circuit Operation
    3. 3.3 Test Results
      1. 3.3.1 Current Sharing
      2. 3.3.2 VLOAD vs ILOAD
      3. 3.3.3 Load Transient Response
      4. 3.3.4 Current Limit
      5. 3.3.5 Startup
      6. 3.3.6 Noise
      7. 3.3.7 PSRR
      8. 3.3.8 Thermal
      9. 3.3.9 Thermal Limit Protection
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  10. 5About the Author

3.3.9 Thermal Limit Protection

The thermal protection performance of the parallel LDOs exhibits a staircase effect on VLOAD during turn off and turn on as each LDO enters and exits thermal shutdown. Thermal protection is repeatedly engaged until the power dissipation from the parallel LDOs is removed. Figure 3-25 demonstrates the desired effect of the thermal protection circuitry in the presence of heavy power dissipation across the LDOs. The parallel LDOs require 12.5 W dissipation in this reference design to enter thermal shutdown when operated from room temperature.

GUID-20221116-SS0I-98W1-JLGS-CGDMS8ZLW2J7-low.png
VIN= 1.9 V, ILOAD = 13.5 A
Figure 3-24 Zoomed in Thermal Shutdown Response
GUID-20221116-SS0I-XGJW-BQN5-QX4FD23W7B5G-low.png
VIN= 2 V, ILOAD = 13.5 A
Figure 3-25 Thermal Shutdown Response Protecting the LDOs