Galvanic-Isolated IGBT Gate Driver IC Evaluation Board

June 03, 2019 by Paul Shepard

The EVAL-1ED020I12-B2 evaluation board from Infineon Technologies demonstrates functionalities and key features of the single-channel galvanic-isolated gate driver IC 1ED020I12-B2 for 600V / 1200V IGBTs. The main features of the board are galvanic isolation, isolation inside the half bridge by defined creepage, short circuit protection, active miller clamp and under voltage lock-out.

Target applications include EV chargers, industrial power systems, motor control & drives, uninterruptible power supplies, smart grid and solar energy systems.

The EVAL-1ED020I12-B2 contains two IGBT gate drivers 1ED020I12-B2 in a half-bridge configuration and an IGBT module FS25R12W1T4_B11 where only two IGBTs are connected. The evaluation board provides the following main features:

  • Galvanic isolation by the coreless transformer technology of the Infineon gate driver. The gate 1ED020I12-B2 is suitable for basic isolation
  • Isolation inside the half bridge by defined creepage
  • Short circuit protection
  • Under voltage lock out
  • Active miller clamp
  • Bootstrap functionality for high side IGBT
  • Connector for 5V digital supply, 15V supply, Reset, High voltage supply, external load
  • Status LED for 5V supply, 15V supply, ready and fault separated for high- and low-side driver
  • DC link capacitor

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Active Miller clamping

On this evaluation board the Infineon gate driver 1ED020I12-B2 is supplied with a unipolar voltage +15V/0V instead of a bipolar supply voltage e.g. +15V/-8V. To avoid a parasitic turn on of the gate by switching on the opposite IGBT, the feature "Active Miller Clamp" of the 1ED020I12-B2 is used. During turn-off, the gate voltage is monitored. If the gate voltage goes below 2V related to VEE2, the clamp output is activated and clamps the gate voltage to VEE2 till an on-command for the gate driver output occurs.

VCEsat monitoring for short circuit detection

The Infineon gate driver 1ED020I12-B2 provides a short circuit detection by measuring the VCEsat voltage of the IGBT. If a short circuit occurs, the collector current and the saturation voltage increase. If the IGBT is commanded on stated and the VCE reaches 9V a short circuit is detected and the gate driver output is switched off. This status is reported by the /FLT signal and the dedicated FAULT LED is switched on. The FAULT status is latched by the 1ED020I12-B2 and must be resetted by switching the RESET Signal to ground.