EPC (Efficient Power Conversion) was founded in November 2007 by three engineers, with a combined 60 years of experience in advanced power management technology. EPC’s mission is to make GaN power devices that are higher performance and lower cost compared with silicon. everything PE recently interviewed Renee Yawger, Director of Marketing at EPC & Director of Corporate Marketing at EPC Space.
Q. Can you give us a brief history of EPC Corp.? When was the company started and what was the objective.
Renee Yawger: EPC (Efficient Power Conversion) was founded in November 2007 by three engineers, with a combined 60 years of experience in advanced power management technology. EPC’s CEO Alex Lidow was the co-inventor of the silicon power MOSFET in the 1970s; and, in addition to holding positions in R&D and manufacturing, was the CEO of International Rectifier for 12 years. It was clear to the founders of EPC that silicon had reached its performance limits, failing to propel innovation forward at the established rate. Thus, EPC was founded with the belief that gallium nitride (GaN) would be the inevitable successor to silicon because of it’s superior performance characteristics. EPC’s mission is to make GaN power devices that are higher performance and lower cost compared with silicon.
Q. Can you tell us about EPC's product portfolio?
Renee Yawger: EPC has over 70 ICs and discrete transistors available for off-the-shelf delivery. Our products range from 15 V – 200 V and soon the product line will extend to 350 V. The initial products were discrete transistors but the product portfolio now includes a rapidly growing offering of integrated devices.
Our first step forward in the integration of functions on a single chip came in September 2014, when EPC launched a family of monolithic half-bridge devices. By integrating two FETs onto a single chip that could be configured as a half bridge, the customer could (a) save a lot of board space, (b) cut the power loop inductance in half, and (c) reduce overshoot that leads to EMI and EMC.
In parallel, work started on adding drivers to power FETs on the same chip. The monolithic devices with drivers reduce the need for an external silicon-based IC driver, and eliminate gate loop inductance. The first commercial products were launched in 2018.
The ultimate goal is to integrate all necessary functions for a complete power conversion solution on a single chip. In March of 2020, EPC released the first in a family of ePower stage devices with the EPC2152, which is a fully monolithic half bridge that integrates all the drive and level-shift functions, along with the bootstrap function.
Q. What are eGaN FETs? How are they different from GaN FETs?
Renee Yawger: GaN FETs can be depletion mode or enhancement mode. Manufacturers that are targeting power applications are primarily presenting enhancement mode devices; either monolithically or via a cascode configuration. EPC only manufactures monolithic enhancement-mode gallium nitride field effect transistors. eGaN® is a registered trademark of EPC. There are other GaN FETs on the market that use the cascode configuration in which the gate of a depletion-mode GaN FET is connected to the source of an enhancement-mode silicon MOSFET so that the final device presents as enhancement mode.
Q. What are the advantages of GaN power transistors over silicon power-MOSFET? How do they compare in terms of performance?
Renee Yawger: Gallium nitride can conduct electrons more efficiently and can withstand higher electric fields than silicon. It exceeds the performance capability of silicon in speed, temperature, power handling and is replacing silicon-based devices in a variety of power conversion and RF applications. The ability of GaN-based systems to offer greater efficiency, significantly reduced size and weight, and improved thermal performance is creating a displacement cycle in traditional silicon markets and enabling new applications such as lidar, the technology that will make autonomous driving a reality.
Q. What about cost? How does the cost of GaN Transistors compare to other power transistors? How can this cost be justified?
Renee Yawger: There is commonly repeated misconception that GaN is more expensive than silicon. In fact, with fewer processing steps, smaller size resulting in more devices per manufacturing run, and in lower voltage (< 500 V) the elimination of expensive packaging, GaN devices can be lower in cost than comparable silicon MOSFTs. And this is before taking into account the system cost savings that can be achieved by taking advantage of the speed and reducing size and cost of magnetics or taking advantage of power density and reducing the number of phases in a system.
Q. How are GaN-based power transistors different from radiation-hardened MOSFETs?
Renee Yawger: Unlike silicon, where special fabrication techniques and special packaging is needed to shield semiconductors from the effects of radiation, GaN’s natural properties make it relatively immune to these harmful rays. GaN power device technology enables a new generation of power converters for operation in the harsh radiation conditions of space. GaN devices are also used in space for the ruggedized high-precision BLDC motors critical for the myriad of robotics and instrumentation used in space missions and in the reaction wheels used to control the attitude of satellites.
Q. What applications and industries benefit from eGaN Power Transistors?
Renee Yawger: The initial adopters of GaN-based power transistors and integrated circuits were those applications taking advantage of the switching speed, such as lidar and RF envelope tracking. As production volumes increased and costs reduced, more traditional applications such as 48 V DC-DC conversion for data centers and computing, drones, robots, consumer products and high-volume automotive applications have adopted GaN solutions.
Q. Can you tell us about some unique products in which EPC FETs/Drivers have been used? How have your FETs/Drivers improved the performance of these products?
Renee Yawger:
Data Center Servers: The growth of the cloud is forcing a corresponding growth in data centers and demand for higher power density converters. Several power supply manufacturers have adopted the unregulated, non-isolated LLC topology using GaN transistors for these applications for state-of-the-art performance in terms of efficiency and power density. An example is the MPS 300 W LLC converter with a power density of 1700 W/in3
Autonomous Vehicles and 3D Sensing: Lidar (light detection and ranging) is the technology that provides the “eyes” for autonomous vehicles. The faster the laser beam in the lidar system can be transmitted, the higher the resolution of the system for enhanced safety. At the core of the lidar system is where GaN plays a vital role – it enables the laser signal to be fired at higher speeds than a comparable silicon component enabling higher resolution and faster response times. Lidar technology is rapidly expanding beyond autonomous vehicles to phones, robots, drones, vacuum cleaners, and security surveillance systems making this a very large market for GaN technology.
Motor Drives: Brushless DC (BLDC) motors are finding increasing applications in robotics, eMobility, and drones. GaN devices reduce size, weight, cost, audible and electric noise, and can eliminate the need for electrolytic capacitors for additional savings and increased reliability.
Space: GaN’s natural properties make it relatively immune to the effects of radiation. This natural immunity and the significant performance advantages compared to Rad Hard silicon MOSFETs make space an inevitable area for many applications including satellite DC-DC converters, reaction wheel motor drives, and ion thrusters.
Q. Is there a learning curve introduced with the use of GaN FETs to develop products rather than using familiar silicon-based solutions? How is EPC addressing this?
Renee Yawger: EPC’s eGaN FETs were designed to behave similarly to silicon power MOSFETs so that designers could leverage their existing knowledge. There are however some key unique characteristics to GaN that engineers should be aware of. EPC provides many resources for the engineer to quickly get up-to-speed and cut the time to market for GaN-based designs.
There are several online tools in the GaN Power Bench™ to assist designers in the selection of the best GaN device for the application, to simulate and optimize the thermal performance of the design, and to provide application examples with all the supporting documentation needed to quickly and easily replicate the optimal design tips necessary for ideal performance.
There are also a series of webinars covering topics all the way from the basics of GaN technology, to intensive tutorials on design tips and studies of real-life application examples.
Also, EPC has literally written the book on GaN power devices and applications. The latest edition was released in late 2021 and is available from the EPC website and from Amazon.
Q. What further advancements are expected in GaN in the next few years?
Renee Yawger: While GaN already offers significantly higher performance than silicon, GaN is still several orders of magnitude away from its theoretical performance limits. We expect to see improvements in the basic figure of merit of the device technology and a rapid migration to more complex integrate devices over the next few years.
Q. What are some factors that can help speed up the adoption of GaN FETs into more devices and end products?
Renee Yawger: There are four main factors that impact the adoption of any new technology and these apply to GaN as well
Applications of GaN
As noted earlier, the initial success of GaN-based FETs and ICs came from the speed advantage of GaN compared with silicon. GaN-on-Si transistors switch about 10 times faster than MOSFETs and 100 times faster than IGBTs. Applications such as RF envelope tracking for 4G/LTE base stations and light detection and ranging (lidar) systems for autonomous cars, robots, drones, and security systems were the first volume applications to take full advantage of GaN’s high-speed switching ability.
GaN integration in devices
GaN transistors are very similar in behavior to power MOSFETs and therefore power systems engineers can use their design experience with minimal additional training.
Additionally, the higher efficiency, increased power density, and lower overall system cost compared to silicon has 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.
The migration to more complex integration also helps to ease adoption. Integrated devices are easier to use, take less space on the PCB, and lower assembly costs.
Cost Effectiveness
GaN transistors and integrated circuits from EPC are produced using processes similar to silicon power MOSFETs, have many fewer processing steps, and more devices are produced per manufacturing run because GaN devices are much smaller than their silicon counterparts. In addition, lower voltage (<500 V) GaN transistors do not require the costly packaging needed to protect their silicon predecessors. This packaging advantage alone can cut the cost of manufacturing in half and, combined with high manufacturing yields and small device size, has resulted in the cost of a GaN transistor from EPC to be lower in cost than a comparable (but slower, bigger) silicon power MOSFET.
Reliability
Several manufacturers of GaN transistors have reported excellent results from in-house stress testing. EPC has established a rigorous reliability program which includes testing parts to the point of failure to establish an understanding of the amount of margin between the data sheet limits, and more importantly, an understanding of the intrinsic failure mechanisms. By knowing the intrinsic failure mechanisms, the root cause of failure, and the device’s behavior over time, temperature, electrical or mechanical stress, the safe operating life of a product can be determined over a more general set of operating conditions.
Q. Can you tell us about how the company has grown over the last few years? What segments or product categories have been responsible for this growth?
Renee Yawger: We have seen the adoption rate for our GaN devices accelerate dramatically in the last few years. The largest growth market in the last few years has been in 48 V DC-DC power supplies for high-density computing applications for cloud computing, artificial intelligence, machine learning, and gaming. In these applications GaN offers significant improvements in switching performance, size reduction, and power density. Looking ahead we expect the largest market drivers to include automotive 48 V systems as the electrification of vehicles is mandated and accelerated, lidar as those systems become simple and inexpensive enough to be incorporated into high-volume consumer products such as cell phones and tablets, motor drives for the rapidly expanding eMobility market, and solar optimizers.
Q. What is your product roadmap for the next 3 years?
Renee Yawger: The future for GaN is GaN integration. With a well-defined and rich set of scalable models, the challenge for further integration shifts to adding even more functionality on a single chip. The ultimate goal is to achieve a single IC component that merely requires a simple digital input from a microcontroller and products a power output that drives a load efficiently, reliability under all conditions, in the smallest space possible, and economically.
About Renee Yawger
Renee Yawger is the Director of Marketing at EPC & Director of Corporate Marketing at EPC Space. Renee has over 25 years of sales and marketing experience within the semiconductor industry. Prior to joining EPC, she was at Vishay Siliconix for nearly 15 years in various positions of sales support, customer service, and regional marketing. At EPC, Renee is responsible for the product marketing and marketing communications functions globally.
