SBAA586 October   2023 AMC23C11 , UCC23513

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2System Challenge on Isolated Gate Drivers With Integrated DESAT
  6. 3System Approach With UCC23513 and AMC23C11
    1. 3.1 System Overview and Key Specification
    2. 3.2 Schematic Design
      1. 3.2.1 Circuit Schematic
      2. 3.2.2 Configure VCE(DESAT) Threshold and DESAT Bias Current
      3. 3.2.3 DESAT Blanking Time
      4. 3.2.4 DESAT Deglitch Filter
    3. 3.3 Reference PCB Layout
  7. 4Simulation and Test Results
    1. 4.1 Simulation Circuit and Results
      1. 4.1.1 Simulation Circuit
      2. 4.1.2 Simulation Results
    2. 4.2 Test Results With 3-Phase IGBT Inverter
      1. 4.2.1 Brake IGBT Test
      2. 4.2.2 Test Results on a 3-Phase Inverter With Phase to Phase Short
  8. 5Summary
  9. 6References
  10. 7Revision History

2 System Challenge on Isolated Gate Drivers With Integrated DESAT

Reinforced isolated smart gate drivers with integrated DESAT function are typically offered in a 16-pin SOIC package, which is physically much larger than a compact gate driver without DESAT function in a stretched SO-6 package, as is shown in Figure 2-1. Consider placing six pieces of such devices of a 3-phase inverter on a power inverter PCB, the package length will stack up accordingly. A design using a shorter length compact device can offer an advantage on the PCB size. Even for a regeneration brake power switch, a smaller size gate driver can help to reduce the application layout area significantly. However, such gate drivers sacrifice the overcurrent protection function for application circuit simplicity and cost reasons.

GUID-20230821-SS0I-85XV-XDGD-1MS6RVSFMCJQ-low.svgFigure 2-1 Package Size Comparison: SO-6 vs. SOIC-16

An alternative approach is to use the smaller footprint compact gate driver without DESAT and implement the DESAT function discretely using an isolated comparator.

For circuit configurations that only require DESAT function on either the three low-side switches or the three high-side ones, this discrete DESAT design allows all six switches to use a same 6-pin reinforced isolated gate driver; thus avoids mixing simple gate drivers with smart gate drivers in one application system. The external DESAT function can be added to the low-side or high-side gate drivers, respectively. This discrete DESAT implementation adds flexibility to the application design to configure parameters of DESAT voltage, DESAT bias current, DESAT detection blanking time, and DESAT output deglitch filter, thus helps to increase immunity against the PWM switching noise.