This image shows Mathias  Weiser

Mathias Weiser

M.Sc.

Research Assistant
Institute of Robust Power Semiconductor Systems

Contact

+49 711 685 61704
+49 711 685 58700

Business card (VCF)

Pfaffenwaldring 47
70569 Stuttgart
Deutschland
Room: 1.444

  1. D. Koch, T. Fink, J. Nuzzo, K. M. Barón, and I. Kallfass, “PCB-Integrated Pickup-Coil for Overcurrent Detection in High-Current, Paralleled GaN HEMTs,” in 2024 IEEE Applied Power Electronics Conference and Exposition (APEC), in 2024 IEEE Applied Power Electronics Conference and Exposition (APEC). Feb. 2024, pp. 555–560. doi: 10.1109/APEC48139.2024.10509108.
  2. R. Schnitzler, D. Koch, M. C. J. Weiser, J. Weimer, and I. Kallfass, “Gate-Source-Dependent Soft- and Hard-Switching Losses of 1200V SiC MOSFETs Utilizing Heatsinkless Calorimetric Measurements Based on Optical Sensors,” in 2024 IEEE Applied Power Electronics Conference and Exposition (APEC), in 2024 IEEE Applied Power Electronics Conference and Exposition (APEC). Feb. 2024, pp. 1100–1107. doi: 10.1109/APEC48139.2024.10509381.
  3. R. Schnitzler, D. Koch, E. Dos Santos Gomes, and I. Kallfass, “Fully Modular, Dynamic SiC and GaN Testbench with Automated Temperature and Gate-Voltage Characterization,” in 2023 IEEE Design Methodologies Conference (DMC), in 2023 IEEE Design Methodologies Conference (DMC). Sep. 2023, pp. 1–6. doi: 10.1109/DMC58182.2023.10412598.
  4. M. Rueß, D. Koch, and I. Kallfass, “Multi-MHz Auto-Resonant Power Oscillator in a 650 V GaN-on-SOI Technology for Compact Wireless Power Transfer Systems,” in 2023 IEEE 10th Workshop on Wide Bandgap Power Devices & Applications (WiPDA), in 2023 IEEE 10th Workshop on Wide Bandgap Power Devices & Applications (WiPDA). Dec. 2023, pp. 1–5. doi: 10.1109/WiPDA58524.2023.10382227.
  5. J. Nuzzo, D. Koch, M. C. J. Weiser, M. Bosch, R. Schnitzler, and I. Kallfass, “Optimized Design of Fast-Switching GaN-based Inverters Utilizing a Digital Prototype in a Standardized Realistic Test Cycle,” in 2023 IEEE Design Methodologies Conference (DMC), in 2023 IEEE Design Methodologies Conference (DMC). Sep. 2023, pp. 1–5. doi: 10.1109/DMC58182.2023.10412404.
  6. D. Koch, J. Nuzzo, M. C. J. Weiser, and I. Kallfass, “Digital Twin for Gate-Resistor Optimization of Parallel, 100 V, 7 mΩ, GaN HEMTs based on Comprehensive Multi-Domain Simulations and Physically-Motivated Transistor Models,” in 2023 IEEE Design Methodologies Conference (DMC), in 2023 IEEE Design Methodologies Conference (DMC). Sep. 2023, pp. 1–5. doi: 10.1109/DMC58182.2023.10412580.
  7. J. Weimer, R. Schnitzler, D. Koch, and I. Kallfass, “Thermal Impedance Calibration for Rapid and Non-Invasive Calorimetric Soft-Switching Loss Characterization,” IEEE Transactions on Power Electronics, pp. 1–14, 2023, doi: 10.1109/TPEL.2023.3267982.
  8. D. Koch, V. Polezhaev, A. B. Sharma, K. M. Barón, T. Huesgen, and I. Kallfass, “Application-Oriented Characterization of Thermally Optimized, Asymmetrical Single Chip Packages for 100 V GaN HEMTs,” in 2023 35th International Symposium on Power Semiconductor Devices and ICs (ISPSD), in 2023 35th International Symposium on Power Semiconductor Devices and ICs (ISPSD). May 2023, pp. 48–51. doi: 10.1109/ISPSD57135.2023.10147544.
  9. D. Koch et al., “Highly-Integrated, Low-Noise, Dual-Output GaN DC/DC for GaN Solid State Power Amplifier Supplies in Space Applications,” in 2023 IEEE 10th Workshop on Wide Bandgap Power Devices & Applications (WiPDA), in 2023 IEEE 10th Workshop on Wide Bandgap Power Devices & Applications (WiPDA). Dec. 2023, pp. 1–6. doi: 10.1109/WiPDA58524.2023.10382198.
  10. J. Weimer, D. Koch, and I. Kallfass, Compact Half-Bridge Module for a Charger Application Utilizing GaN Power Devices with Integrated Driver. VDE VERLAG GMBH, 2022. doi: 10.30420/565822282.
  11. D. Koch, A. Sharma, T. Huesgen, and I. Kallfass, “Comparison of Thermally Optimized SMD Packages for 100 V GaN HEMTs in 300 kHz Buck Converter High Current Applications,” in 2022 IEEE 9th Workshop on Wide Bandgap Power Devices & Applications (WiPDA), in 2022 IEEE 9th Workshop on Wide Bandgap Power Devices & Applications (WiPDA). Nov. 2022, pp. 204–208. doi: 10.1109/WiPDA56483.2022.9955270.
  12. J. Weimer, D. Koch, M. Nitzsche, J. Haarer, J. Roth-Stielow, and I. Kallfass, “Miniaturization and Thermal Design of a 170 W AC/DC Battery Charger Utilizing GaN Power Devices,” IEEE Open Journal of Power Electronics, vol. 3, pp. 13–25, 2022, doi: 10.1109/OJPEL.2021.3137093.
  13. D. Koch, D. Wrana, B. Schoch, and I. Kallfass, “Low-Noise, 24 V, 1 A, 2.1 MHz GaN DC/DC Converter for Variable Power Supply of a GaN-Based Solid-State Power Amplifier,” in 2022 IEEE Applied Power Electronics Conference and Exposition (APEC), in 2022 IEEE Applied Power Electronics Conference and Exposition (APEC). Mar. 2022, pp. 1208–1213. doi: 10.1109/APEC43599.2022.9773463.
  14. J. Weimer, D. Koch, R. Schnitzler, and I. Kallfass, “Determination of Hard- and Soft-Switching Losses for Wide Bandgap Power Transistors with Noninvasive and Fast Calorimetric Measurements,” in 2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD), in 2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD). May 2021, pp. 327–330. doi: 10.23919/ISPSD50666.2021.9452230.
  15. J. Weimer, D. Koch, and I. Kallfass, “Accuracy Study of Calorimetric Switching Loss Energy Measurements for Wide Bandgap Power Transistors,” in 2021 23rd European Conference on Power Electronics and Applications (EPE’21 ECCE Europe), in 2021 23rd European Conference on Power Electronics and Applications (EPE’21 ECCE Europe). 2021, p. P.1-P.9.
  16. D. Koch, H. Bantle, J. Acuna, P. Ziegler, and I. Kallfass, “Design Methodology for Ultra-Compact Rogowski Coils for Current Sensing in Low-Voltage High-Current GaN Based DC/DC-Converters,” in 2021 23rd European Conference on Power Electronics and Applications (EPE’21 ECCE Europe), in 2021 23rd European Conference on Power Electronics and Applications (EPE’21 ECCE Europe). 2021, p. P.1-P.9.
  17. D. Koch, M. Rueß, D. Maier, and I. Kallfass, “Optimization of Self-Oscillating Power Converter Based on GaN HEMTs for Wireless Power Transfer,” in 2021 IEEE 8th Workshop on Wide Bandgap Power Devices and Applications (WiPDA), in 2021 IEEE 8th Workshop on Wide Bandgap Power Devices and Applications (WiPDA). Nov. 2021, pp. 164–169. doi: 10.1109/WiPDA49284.2021.9645129.
  18. M. Nitzsche, J. Haarer, J. Weimer, D. Koch, and J. Roth-Stielow, “Influence Analysis of Thermally Conductive Epoxy Resin on the Electrical Design of a Compact AC/DC Converter,” in 2021 IEEE Energy Conversion Congress and Exposition (ECCE), in 2021 IEEE Energy Conversion Congress and Exposition (ECCE). Oct. 2021, pp. 5677–5683. doi: 10.1109/ECCE47101.2021.9594931.
  19. J. Weimer, D. Koch, M. Nitzsche, J. Haarer, J. Roth-Stielow, and I. Kallfass, “Miniaturization and Thermal Design of a 170 W AC/DC Battery Charger Utilizing GaN Power Devices,” IEEE Open Journal of Power Electronics, pp. 1–1, 2021, doi: 10.1109/OJPEL.2021.3137093.
  20. D. Koch, S. Araujo, J. Weimer, and I. Kallfass, “Automated Calorimetric Measurement with a Peltier Element for Switching Loss Characterization,” in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. May 2021, pp. 1–8. [Online]. Available: https://ieeexplore.ieee.org/document/9472391
  21. J. Weimer, D. Koch, M. Nitzsche, J. Haarer, and I. Kallfass, “Thermal Topology Optimization for High Power Density Power Electronic Systems in Passively Cooled Housings,” in 2021 IEEE Design Methodologies Conference (DMC), in 2021 IEEE Design Methodologies Conference (DMC). Jul. 2021, pp. 1–6. doi: 10.1109/DMC51747.2021.9529942.
  22. D. Koch, A. Sharma, J. Weimer, M. Weiser, T. Huesgen, and I. Kallfass, “A 48 V, 300 kHz, High Current DC/DC-Converter Based on Paralleled, Asymmetrical  Thermally Optimized PCB Embedded GaN Packages with Integrated Temperature Sensor,” in 2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD), in 2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD). May 2021, pp. 383–386. doi: 10.23919/ISPSD50666.2021.9452241.
  23. R. Loeffler, J. Hueckelheim, D. Koch, and I. Kallfass, “Development of a Powerful Gate-Driver-Circuit for High-Frequency Control of a DC/DC-Converter Based on Gallium Nitride Transistors,” in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. May 2021, pp. 1–7. [Online]. Available: https://ieeexplore.ieee.org/document/9472436
  24. A. B. Sharma, J. Weimer, D. Koch, I. Kallfass, and T. Huesgen, “Asymmetric Packages for Optimal Performance of GaN-HEMT using PCB Fabrication Technology,” in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2021; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. May 2021, pp. 1–8. [Online]. Available: https://ieeexplore.ieee.org/document/9472333
  25. D. Koch, J. Weimer, M. Weiser, J. Hueckelheim, and I. Kallfass, “Gate Driver Concept for Parallel Operation of Low-Voltage High-Current GaN Power Transistors for Mild-Hybrid Applications,” in 2021 IEEE Applied Power Electronics Conference and Exposition (APEC), in 2021 IEEE Applied Power Electronics Conference and Exposition (APEC). Jun. 2021, pp. 1755–1760. doi: 10.1109/APEC42165.2021.9487194.
  26. J. Weimer, D. Koch, M. Nitzsche, M. Zehelein, and I. Kallfass, “Efficiency Requirements for Passively Cooled Converters with Thermal Measurement Based 3D-FEM Simulation,” in 2020 22nd European Conference on Power Electronics and Applications (EPE’20 ECCE Europe), in 2020 22nd European Conference on Power Electronics and Applications (EPE’20 ECCE Europe). Sep. 2020, pp. 1–8. doi: 10.23919/EPE20ECCEEurope43536.2020.9215643.
  27. D. Koch et al., “Static and Dynamic Characterization of a Monolithic Integrated Temperature Sensor in a 600 V GaN Power IC,” in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. Jul. 2020, pp. 1–7. [Online]. Available: https://ieeexplore.ieee.org/document/9178102
  28. K. Munoz Baron, K. Sharma, M. Nitzsche, P. Ziegler, D. Koch, and I. Kallfass, “Characterization of Threshold Voltage for Application-Oriented Power Cycling Conditions for Wide-Bandgap Power Devices,” in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. Jul. 2020, pp. 1–7. [Online]. Available: https://ieeexplore.ieee.org/document/9178169
  29. K. Sharma et al., “Characterization of the Junction Temperature of SiC Power Devices via Quasi-Threshold Voltage as Temperature Sensitive Electrical Parameter,” in CIPS 2020; 11th International Conference on Integrated Power Electronics Systems, in CIPS 2020; 11th International Conference on Integrated Power Electronics Systems. Mar. 2020, pp. 1–6. [Online]. Available: https://ieeexplore.ieee.org/document/9097714
  30. M. Nitzsche, M. Zehelein, J. Weimer, D. Koch, and J. Roth-Stielow, “Design Flow of a Compact High-Frequency DC/DC Converter with Optimum Average Efficiency in a Wide Operation Range,” in 2020 22nd European Conference on Power Electronics and Applications (EPE’20 ECCE Europe), in 2020 22nd European Conference on Power Electronics and Applications (EPE’20 ECCE Europe). Sep. 2020, p. P.1-P.12. doi: 10.23919/EPE20ECCEEurope43536.2020.9215933.
  31. J. Weimer, A. B. Sharma, T. Huesgen, D. Koch, and I. Kallfass, “Thermal Study on Leadframe Dimensioning for High Power Dissipation and Low Inductance Commutation Cells,” in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, in PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management. Jul. 2020, pp. 1–8. [Online]. Available: https://ieeexplore.ieee.org/document/9178107
  32. D. Koch, S. Araujo, and I. Kallfass, “Accuracy Analysis of Calorimetric Loss Measurement for Benchmarking Wide Bandgap Power Transistors under Soft-Switching Operation,” in 2019 IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia), in 2019 IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia). May 2019, pp. 1–6. doi: 10.1109/WiPDAAsia.2019.8760332.
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