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2020-04-24
Overgaard, Jacob E. F., Hertel, Jens Christian, Pejtersen, Jens, Knott, Arnold.  2018.  Application Specific Integrated Gate-Drive Circuit for Driving Self-Oscillating Gallium Nitride Logic-Level Power Transistors. 2018 IEEE Nordic Circuits and Systems Conference (NORCAS): NORCHIP and International Symposium of System-on-Chip (SoC). :1—6.
Wide bandgap power semiconductors are key enablers for increasing the power density of switch-mode power supplies. However, they require new gate drive technologies. This paper examines and characterizes a fabricated gate-driver in a class-E resonant inverter. The gate-driver's total area of 1.2mm2 includes two high-voltage transistors for gate-driving, integrated complementary metal-oxide-semiconductor (CMOS) gate-drivers, high-speed floating level-shifter and reset circuitry. A prototype printed circuit board (PCB) was designed to assess the implications of an electrostatic discharge (ESD) diode, its parasitic capacitance and package bondwire connections. The parasitic capacitance was estimated using its discharge time from an initial voltage and the capacitance is 56.7 pF. Both bondwires and the diode's parasitic capacitance is neglegible. The gate-driver's functional behaviour is validated using a parallel LC resonant tank resembling a self-oscillating gate-drive. Measurements and simulations show the ESD diode clamps the output voltage to a minimum of -2V.
2019-12-17
Huang, Hsiang-Hung, Toprasertpong, Kasidit, Delamarre, Amaury, Watanabe, Kentaroh, Sugiyama, Masakazu, Nakano, Yoshiaki.  2019.  Numerical Demonstration of Trade-off between Carrier Confinement Effect and Carrier Transport for Multiple-Quantum-Well Based High-Efficiency InGaP Solar Cells. 2019 Compound Semiconductor Week (CSW). :1-2.

To promote InGaP solar cell efficiency toward the theoretical limit, one promising approach is to incorporate multiple quantum wells (MQWs) into the InGaP host and improve its open-circuit voltage by facilitating radiative carrier recombination owing to carrier confinement. In this research, we demonstrate numerically that a strain-balanced (SB) In1-xGaxP/In1-yGayP MQW enhances confined carrier density while degrades the effective carrier mobility. However, a smart design of the MQW structure is possible by considering quantitatively the trade-off between carrier confinement effect and carrier transport, and MQW can be advantageous over the InGaP bulk material for boosting photovoltaic efficiency.