IR Camera Validation of IGBT Junction Temperature Measurement via Peak Gate Current
Nick Baker, Laurent Dupont, Stig Munk‐Nielsen, Francesco Iannuzzo, Marco Liserre
Aalborg University, Denmark and IFSTTAR, France
Abstract: Infra-red measurements are used to validate the Peak Gate Current method for IGBT junction temperature measurement.
Single IGBT chips with the gate pad in both the centre and the edge are investigated, along with paralleled chips, as well as chips
suffering partial bond-wire lift-off. Results are also compared with a well established electrical temperature measurement method: the
voltage drop under low current. The Peak Gate Current is found to provide a temperature slightly overestimating the temperature of the
gate pad. Consequently, both the gate pad position and chip temperature distribution have an influence on whether the measurement
adequately represents the mean junction temperature. These results remain consistent after chips are degraded through bondwire lift-off.
Peak Gate Current ‐ IGPeak
‐ Does not require load current compensation
‐ Relatively simple measurement circuit – peak detector
controlled by the gate signal
‐ Recently proposed – requires validation and comparison with
other electrical temperature measurement methods
Test Bench, IR camera and DUT IGBTs
Schematic of Peak Detector Circuit
DUT IGBTs
13.62mm
13.78mm
‐ Steady state current injection, 300A current supply
‐ 10‐15min DC current heating phase, temperature measurements
at the end of heating phase
‐ 2 types of Infineon IGBTs rated at 1200V/200A – differing geometry
Prototype Measurement
Circuit with Gate Driver
IGBT A: Infineon IGC189T120T8RL
15.99mm
12.08mm
Panoramic view of test bench with IR Camera, and close up of open power module and gate driver
IGBT B: Infineon IGC193T120T8RM
Results
‐ IGPeak provides a temperature related to the temperature of the gate pad
 Higher than the chip mean surface temperature when the gate pad is in the centre (IGBT A)
 Lower than the chip mean surface temperature when the gate pad is at the edge (IGBT B)
IGPeak temperature measurement vs. temperature
of the gate pad measured via IR camera
Future Work
Temperature measurement results
during current injection
Electrical temperature measurements vs. mean
chip temperature measured via IR camera
‐ Implement in real functional
conditions
‐ Apply to MOSFETs and wide‐
bandgap devices