Wide Bandgap and Double Pulse Test

What is a Wide Bandgap (WBG)? 

A Wide Bandgap (WBG) refers to semiconductor materials with a larger bandgap compared to traditional materials like Silicon (Si). The bandgap is the energy required to move an electron from the valence band to the conduction band, enabling electrical conduction.

Key WBG materials include Silicon Carbide (SiC) and Gallium Nitride (GaN), which exhibit superior characteristics such as:

1. Higher thermal conductivity and temperature tolerance
   WBG devices can operate at much higher temperatures than Silicon.
2. Lower energy losses
   WBG materials have lower conduction and switching losses, making them highly efficient.
3. Higher voltage handling capability
   They support higher breakdown voltages, making them suitable for high-power applications.
4. Faster switching speeds
   WBG materials allow higher-frequency operation, reducing the size of passive components.
5. Enhanced reliability and durability
   They are more robust under extreme conditions such as high temperatures and voltages.

Setting up Measurements for Wide Bandgap and Double Pulse Test

To effectively measure WBG devices using the Double Pulse Test (DPT), follow these steps:
 

1. Circuit Configuration

• Device Under Test (DUT):
  The DUT can be a SiC/GaN MOSFET, diode, or other power devices.
• Driver Circuit:
  Use a gate driver to generate accurate pulse signals for driving the DUT.
• Load and Measurement Components:
  Include inductive loads to simulate realistic operating conditions and use precision probes to capture waveforms.
• Deskew Adjustments:
  Use WBG-specific deskew features to compensate for time delays between voltage and current measurements.

2. Double Pulse Test Setup

• Pulse Timing Parameters:
  • First Pulse Duration: Determines the on-state of the device and its steady-state performance.
  • Second Pulse Duration: Captures dynamic switching characteristics and recovery behavior.
  • Pulse Gap: Adjust to allow stabilization between the pulses for accurate transient analysis.
• Voltage and Current Probes:
  • Use high-bandwidth probes for capturing high-speed transients.
  • Ensure optical differential isolation with to avoid ground loops.

3. Measurement Configurations

• Key Parameters to Measure:
  • Switching Parameters:
    • Rise time ($t_r$) and fall time ($t_f$)
    • Turn-on delay ($t_{on}$) and turn-off delay ($t_{off}$)
  • Diode Recovery:
    • Reverse recovery time ($T_{rr}$) and reverse recovery current ($I_{rr}$)
  • Dynamic Rds(on):
    • Evaluate on-state resistance variations during operation.
• Custom Reference Levels:
  Configure start and stop levels for precise measurement of switching transitions.
• Hysteresis Settings:
  Avoid false triggers by configuring gate-source hysteresis levels.

4. Annotations and Analysis

• Waveform Annotations:
  Add visual markers to highlight critical regions of operation, such as first pulse, second pulse, and recovery transitions.
• Graph Overlays:
  Overlay plots to compare reverse recovery times and currents.
• Search Directions:
  Use forward and backward search to navigate through pulse events effectively.

5. Automation and Data Handling

• Automated Measurements:
  Use pre-configured settings compliant with JEDEC and IEC standards for repeatable and reliable results.
• Programmatic Control:
  Utilize APIs or programmatic interfaces for full automation of testing procedures.
• Scalability:
  Optimize test setups for high-volume testing with flexible configurations for various DUTs.

Advantages of the Wide Bandgap Double Pulse Test

1. Time and Cost Efficiency:
   Rapid setup and automated measurements save time during testing and debugging.
2. Enhanced Accuracy:
   High-precision measurements ensure accurate device characterization.
3. Debugging and Optimization:
   Advanced analysis tools aid in refining designs and improving performance.
4. Standards Compliance:
   Built-in compliance with JEDEC and IEC standards simplifies validation and certification processes.

By following these guidelines, you can set up and execute reliable, high-precision measurements for Wide Bandgap devices, enabling efficient testing and development in power electronics.