SLVUCB8A May   2022  – September 2022 TPS25985

 

  1.   TPS25985 evaluation module for eFuse User's Guide
  2.   Trademarks
  3. 1Introduction
    1. 1.1 EVM Features
    2. 1.2 EVM Applications
  4. 2Description
  5. 3Schematic
  6. 4General Configurations
    1. 4.1 Physical Access
    2. 4.2 Test Equipment and Setup
      1. 4.2.1 Power supplies
      2. 4.2.2 Meters
      3. 4.2.3 Oscilloscope
      4. 4.2.4 Loads
  7. 5Test Setup and Procedures
    1. 5.1  Hot Plug
    2. 5.2  Start-up with Enable
    3. 5.3  Difference Between Current Limit and DVDT Based Start-up Mechanisms
    4. 5.4  Power-up into Short
    5. 5.5  Overvoltage Lockout
    6. 5.6  Transient Overload Performance
    7. 5.7  Overcurrent Event
    8. 5.8  Provision to Apply Load Transient and Overcurrent Event Using an Onboard Switching Circuit
    9. 5.9  Output Hot Short
    10. 5.10 PROCHOT# Implementation Using General-Purpose Comparator
    11. 5.11 Quick Output Discharge (QOD)
    12. 5.12 Thermal Performance of TPS25985EVM
  8. 6EVAL Board Assembly Drawings and Layout Guidelines
    1. 6.1 PCB Drawings
  9. 7Bill Of Materials (BOM)
  10. 8Revision History

5.9 Output Hot Short

Use the following instructions to perform the output hot short test:

  1. Set the input supply voltage VIN to 12 V and connect the power supply between VIN (Connector T1) and PGND (Connector T3).
  2. Turn ON the power supply.
  3. Short the output of the device for example, VOUT (Connector T2) to PGND (Connector T3) through a shorter cable, which is just enough to insert a 150 A current probe.
  4. Observe the waveforms using an oscilloscope.

Figure 5-15 shows the test waveforms of output hot short on the TPS25985EVM with two (2) TPS25985 eFuses in parallel.

Figure 5-15 Output Hot Short Response in TPS25985EVM (VIN = 12 V, RIMON = 1.11 ∥ 1.1 kΩ, RIREF = 40.2 kΩ, and COUT = 10 µF)
Tip: Make sure there is sufficient input capacitor to eliminate voltage dips at the input. A combination of electrolytic and ceramic capacitors are preferred. With these capacitors, a large current can be provided for a short period of time during short-circuit.
Note: It is very difficult to obtain repeatable and similar short-circuit testing results. The following contributes to the variation in results:
  • Source bypassing
  • Input leads
  • Board layout
  • Component selection
  • Output shorting method
  • Relative location of the short
  • Instrumentation
The actual short exhibits a certain degree of randomness because it microscopically bounces and arcs. Ensure that configuration and methods are used to obtain realistic results. Hence, do not expect to see waveforms exactly like the waveforms in this user's guide because every setup is different.