Elimination of voltage overshoot
The active gate driver almost entirely eliminates voltage overshoot in hard-switched circuits, as shown in the figure. Here, the gate current of the low-side 40 V GaN device in a bridge leg is being actively manipulated at turn on, to eliminate the voltage overshoot on the high-side device as it turns off.
Equally, current overshoot can be dampened, which we visualise using best-in-class current sensors developed in collaboration with RAM Innovations Ltd (Bandwidth: >300 MHz for mains voltage circuits, 2 GHz for 40 V circuits. Insertion inductance 0.2 nH at 1 GHz). Other reports on waveform shaping are referenced from the following pages.
References
H.C.P.Dymond, D.Liu, Jeremy J. O. Dalton, J. Wang and B. H. Stark, "Multi-level active gate driver for SiC MOSFETs", IEEE ECCE, 2017.
J. Wang, J.Dalton, H.C.P. Dymond, D. Liu, B.H.Stark, "Crosstalk Suppression in a 650-V GaN FET Bridge-leg Converter using 6.7-GHz Active Gate Driver", IEEE ECCE 2017.
J. Dalton, J. Wang, D. Liu, H. C. P. Dymond, N. McNeill, D. Pamunuwa, S. J. Hollis, B. H. Stark, “Shaping switching waveforms in a 650 V GaN FET bridge-leg using a 6.7 GHz active gate driver”, IEEE APEC 2017
H. C. P. Dymond, D. Liu, J. Wang, J. Dalton, N. McNeill, D. Pamunuwa, S. J. Hollis, B. H. Stark, “Reduction of oscillations in a GaN bridge leg using active gate driving with sub-ns resolution, arbitrary gate-impedance patterns”, IEEE ECCE, Milwaukee, 2016. Won a best paper award at IEEE ECCE 2016.
PhD Opportunities
Interested in the electric revolution, future of transport or Power Electronics? We're looking for enthusiastic and motivated students to join the EEMG.
Fully funded PhD scholarships for Chinese students to carry out research at the University of Bristol
Contact
To trial our active gate driver ICs, please contact Bernard Stark.
We are keen to work with companies to develop drivers for specific applications, and to help other research groups and companies set up test benches using our ICs.