TIDUF75 April   2025

 

  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 System Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1  Determining the Number of eFuse Devices to use in Parallel
      2. 2.2.2  Setting up the Primary and Secondary Devices in a Parallel Configuration
      3. 2.2.3  Selecting the CDVDT Capacitor to Control the Output Slew Rate and Start-Up Time
      4. 2.2.4  Selecting the RIREF Resistor to set the Reference Voltage for Overcurrent Protection and Active Current Sharing
      5. 2.2.5  Selecting the RIMON Resistor to set the Overcurrent (Circuit Breaker) and Fast-Trip Thresholds During Steady-State
      6. 2.2.6  Selecting the RILIM Resistor to set the Current Limit and Fast-Trip Thresholds During Start-Up and the Active Sharing Threshold During Steady-State
      7. 2.2.7  Selecting the CITIMER Capacitor to Set the Overcurrent Blanking Timer
      8. 2.2.8  Selecting the Resistors to set the Under-voltage Lockout Threshold
      9. 2.2.9  Selecting the R-C Filter Between VIN and VDD
      10. 2.2.10 Selecting the Pullup Resistors and Power Supplies for SWEN, PG, FLT, and CMPOUT Pins
      11. 2.2.11 TVS Diode Selection at Input and Schottky Diode Selection at Output
      12. 2.2.12 Selecting CIN and COUT
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS25985
      2. 2.3.2 LM94022 and LM94022-Q1
      3. 2.3.3 INA241x
      4. 2.3.4 TLV760
      5. 2.3.5 SN74LVC1G123
      6. 2.3.6 UCC27511A
      7. 2.3.7 CSD18510Q5B
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1.      36
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 Bill of Materials
      3. 4.1.3 Altium Project
      4. 4.1.4 Gerber Files
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.2.1 Determining the Number of eFuse Devices to use in Parallel

By factoring in a small variation in the junction-to-ambient thermal resistance (RθJA), a single TPS25985x eFuse is rated at a maximum steady state DC current of 60A with a maximum junction temperature of less than 125°C. Considering further degradation of RθJA of each eFuse due to the placement of multiple devices connected in parallel, each device is assumed to be rated for a thermal design current (TDC) of 50A at an elevated ambient temperature of 70°C.

Therefore, Equation 1 can be used to calculate the number of parallel devices (N) to support the maximum steady-state DC load current (ILOAD(max)), for which to model the design.

Equation 1. N≥IOUTmax A50A

According to Table 1-1, IOUT(max) is 300A. Therefore, six (6) TPS25985 eFuses are connected in parallel in the TIDA-050077.