SLVUD40 November   2024 TPS25984B

 

  1.   1
  2.   TPS25984BEVM: Evaluation Module for TPS25984B eFuse
  3.   Trademarks
  4. 1Introduction
    1. 1.1 EVM Features
    2. 1.2 EVM Applications
  5. 2Description
  6. 3Schematic
  7. 4General Configurations
    1. 4.1 Physical Access
    2. 4.2 Test Equipment
      1. 4.2.1 Power Supplies
      2. 4.2.2 Meters
      3. 4.2.3 Oscilloscope
      4. 4.2.4 Loads
  8. 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  Output Hot Short
    9. 5.9  Quick Output Discharge (QOD)
    10. 5.10 Thermal Performance of TPS25984BEVM
  9. 6EVAL Board Assembly Drawings and Layout Guidelines
    1. 6.1 PCB Drawings
  10. 7Bill of Materials (BOM)

5.3 Difference Between Current Limit and DVDT Based Start-Up Mechanisms

Use the following instructions to perform the start-up with current limit test:
  1. Configure the jumper J2 position to the desired slew rate mentioned in Table 4-3.
  2. Configure the jumpers J5 and J7 positions to the desired current limits as mentioned in Table 4-3.
  3. Configure the Jumper J6 position to desired reference voltage for overcurrent protection as mentioned in Table 4-3.
  4. Set the input supply voltage VIN to 12V and current limit to 100A.
  5. Connect a load of 0.9Ω between VOUT (Connector T2) and PGND (Connector T3).
  6. Connect the input supply between VIN (Connector T1) and PGND (Connector T3).
  7. Turn on the power supply by keeping the device disabled using the switch SW1.
  8. Enable the eFuse by releasing the switch SW1.
  9. Observe the waveform at VOUT (TP6) and input current using an oscilloscope. The main intention of this experiment is to observe the output voltage and input current profiles and time required to complete the inrush with two different ILIM set points having all other test conditions identical. The inrush current hits the current limit set point in one case, but does not in the next.

Figure 5-6 and Figure 5-7 show the difference between the current limit and DVDT based start-up mechanisms on the TPS25984BEVM eFuse evaluation board having two (2) devices in parallel for RILIM of 2.8kΩ, RLIM2 of 2.8kΩ, RILIM of 1.65kΩ, and RLIM2 of 1.65kΩ.

TPS25984BEVM Start-Up With Current Limit Response of TPS25984B eFuse
VIN = 12V, EN stepped up from 0V to 3V, RILIM = 2.8kΩ, RLIMI2 = 2.8kΩ, RIREF = 50kΩ, COUT = 18.47mF, RLOAD = 0.9Ω, and CDVDT = 43nF
Figure 5-6 Start-Up With Current Limit Response of TPS25984B eFuse
TPS25984BEVM Start-Up With Output Slew Rate Control (Only) Response of TPS25984B eFuse
VIN = 12V, EN stepped up from 0V to 3V, RILIM = 1.65kΩ Ω, RILIM2 = 1.65kΩ Ω, RIREF = 50kΩ, COUT = 18.47mF, RLOAD = 0.9Ω, and CDVDT = 43nF
Figure 5-7 Start-Up With Output Slew Rate Control (Only) Response of TPS25984B eFuse