Rethinking the Ordinary and Overcoming Mental Biases

Motor drive applications span several markets: industrial, appliance, and automotive. A commonality that occurs regardless of market is that when a new technology is proposed, it faces resistance to its adoption; after all, it is human nature to stick with what is known and resist change.

Efficient Power Conversion (EPC) is increasing the performance distance between the aging silicon power MOSFET and eGaN transistors with 100 V ratings.  The new fifth-generation “plus” devices have about 20% lower R_DS(on) and increased DC ratings compared with the prior fifth-generation products.  This performance boost comes from the addition of a thick metal layer and a conversion from solder balls to solder bars.

Packaged SEE Immune and Radiation Hardened enhancement mode gallium nitride (eGaN) devices offer dramatically improved performance over the aging Rad Hard silicon MOSFET, enabling a new generation of power converters in space operating at higher frequencies, higher efficiencies, and greater power densities than ever achievable before.

Dear Friends, colleagues and partners of EPC,

Happy New Year to you and your family from all of us at EPC!

2019 was a year to remember for EPC’s GaN innovations and the multiple use cases for GaN that have come to fruition. EPC’s latest generation of GaN products have enabled engineers to gain power stage advantages due to their low R_DS(on) characteristics, higher efficiency, enhanced thermal properties, small size and low cost. Now, more than ever, power system designers are switching from silicon devices to higher performance GaN components.

Silicon has been around long enough. It’s time for a younger and far more fit challenger to take over semiconductor material dominance.

When I first started developing power devices 44 years ago, the “king of the hill” was the silicon power bipolar transistor.  In 1978 International Rectifier (IRF) launched power MOSFETs as a faster alternative to the slower and aging bipolar devices.  The early adopters of the power MOSFET were applications where the bipolar just was not fast enough.  The signature example for its adoption was the switching power supply for the desktop computer; first at Apple, and then at IBM. 

With advancements in motor technology, power densities have increased; motors are built in smaller form factors and designed for higher speeds, and higher precision, which requires higher electrical frequencies.

3-phase brushless DC (BLDC) motors are compact for their power ratings, can be precisely controlled, offer high electro-mechanical efficiency, and can operate with minimal vibration when properly controlled. These motors are increasingly or exclusively used in precision applications like servo drives, robotics, such as surgical robots, and drones, such as quadcopters. To keep current ripple within a reasonable range, these motors – given their low inductance – require switching frequencies up to 100kHz. A FET that can operate efficiently at high frequency is required to minimize losses and offset the torque ripple in the motor which creates vibrations, reduces drive precision and decreases efficiency.

This post was originally published by M. Di Paolo Emilio on the Power Electronic News web site.

Power switching devices based on gallium nitride technology (GaN) are in volume production now and delivering high efficiency and power density in real-world power applications. This article will examine how to implement high-power solutions with GaN technology, presenting application examples that demonstrate how GaN devices can effectively work even beyond 600 volts.

GaN devices differ from best-in-class field-effect transistors (FETs) and other silicon-based components in several important respects. GaN devices enable solutions that increase power density by two or more times over silicon-based approaches. As a result, component and package size can be reduced, yielding a solution with a smaller PCB footprint. GaN devices also offer higher efficiency than their silicon predecessors, albeit at a comparably higher overall system cost.

eGaN® FET-based power conversion systems offer higher efficiency, increased power density, and lower overall system cost than Si-based alternatives. These advantageous characteristics have spurred the presence of an ever increasing ecosystem of power electronics components such as gate drivers, controllers, and passive components that specifically enhance eGaN FET performance. Some examples of eGaN FETs are shown in figure 1.

The rapid expansion of the computing and telecommunication market is demanding an ever more compact, efficient and high power density solution for intermediate bus converters. The LLC resonant converter is a remarkable candidate to provide a high power density and high efficiency solution. eGaN® FETs with their ultra-low on-resistance and parasitic capacitances, benefit LLC resonant converters by significant loss reduction that is challenging when using Si MOSFETs. A 48 V to 6 V, 900 W, 1 MHz LLC DC to DC transformer (DCX) converter employing eGaN FETs such as EPC2053 and EPC2023 is demonstrated, yielding a peak efficiency of 98.1% with a specific power of 48 W/cm2 (308 W/in2) and power density of 69 W/cm3 (1133 W/in3).

As the new year starts, it is worth spending a few minutes to review the successes of 2018 and look ahead to expectations for 2019. 

Over the past year, the applications taking advantage of GaN’s superior performance continued to expand and the knowledge base of GaN users continued to broaden.  The world has seen in operation the autonomous vehicles that GaN enables. Digital communications have been vastly improved with the use of GaN FETs and ICs in high speed, energy saving envelope tracking power supplies. The dream of a wireless world is coming closer to reality with the emergence of large surface area wireless power.