Gallium nitride semiconductor technology is transforming many industrial fields due to its ability to work better and more efficiently than standard silicon-based parts. GaN has many benefits, such as a wide bandgap, high electron mobility and strong chemical bonds. These properties have led to widespread use in many applications requiring small size, high power density and heat resistance.
LiDAR systems for self-driving cars, high-frequency motor drives in robots and drones, and power conversion in data centers are just a few of the areas benefiting from GaN technology. In this article, we explore the impact of GaN through insights from Alex Lidow, CEO of Efficient Power Conversion (EPC), a pioneering manufacturer of GaN integrated circuits (ICs). Lidow delves into GaN’s applications in motor control and LiDAR.
GaN in various applications
GaN technology first reached a tipping point in light detection and ranging (LiDAR) applications for measuring distances with high precision. The ability to generate extremely high-current light pulses of very short duration is critical for time-of-flight LiDAR systems to accurately determine when photons are emitted and received. GaN’s faster switching speeds and lower parasitic inductance compared with silicon allowed it to excel in this role from the outset.
Another early adopter of GaN was the IT server industry, specifically for high-density cloud servers, bitcoin mining rigs and, more recently, AI servers. As these servers transitioned from 12-V to 48-V distribution to meet increasing current demands, GaN enabled smaller, more efficient 48-V to 12-V on-board power converters. Within just a few years, GaN completely replaced silicon in this application.
Gallium nitride semiconductor technology is transforming many industrial fields due to its ability to work better and more efficiently than standard silicon-based parts. GaN has many benefits, such as a wide bandgap, high electron mobility and strong chemical bonds. These properties have led to widespread use in many applications requiring small size, high power density and heat resistance.
LiDAR systems for self-driving cars, high-frequency motor drives in robots and drones, and power conversion in data centers are just a few of the areas benefiting from GaN technology. In this article, we explore the impact of GaN through insights from Alex Lidow, CEO of Efficient Power Conversion (EPC), a pioneering manufacturer of GaN integrated circuits (ICs). Lidow delves into GaN’s applications in motor control and LiDAR.
GaN in various applications
GaN technology first reached a tipping point in light detection and ranging (LiDAR) applications for measuring distances with high precision. The ability to generate extremely high-current light pulses of very short duration is critical for time-of-flight LiDAR systems to accurately determine when photons are emitted and received. GaN’s faster switching speeds and lower parasitic inductance compared with silicon allowed it to excel in this role from the outset.
Another early adopter of GaN was the IT server industry, specifically for high-density cloud servers, bitcoin mining rigs and, more recently, AI servers. As these servers transitioned from 12-V to 48-V distribution to meet increasing current demands, GaN enabled smaller, more efficient 48-V to 12-V on-board power converters. Within just a few years, GaN completely replaced silicon in this application.
To further enhance LiDAR performance, GaN ICs have been developed that incorporate the laser driver and other functions like gate drives on the same chip. This monolithic implementation eliminates parasitic inductances from interconnects, enabling pulse rise times as short as 20 picoseconds with currents up to 125 A.
Such advanced GaN ICs are key enablers for long-range, high-resolution LiDAR systems in applications like autonomous vehicles. They also help mitigate signal noise from other LiDAR sources by facilitating unique pulse-coding techniques that rapid-fire specific sequences of laser pulses.
GaN in motor control: power and efficiency
Motor control is another key area where GaN technology drives major performance gains over traditional silicon-based motor drives. Brushless DC motors in applications like drones, robotics, power tools and e-bikes are commonly driven using a three-phase circuit that pulses the motor windings to generate rotation.
However, silicon MOSFETs used in these drives have an inherent limitation: MOSFETs contain a reverse-recovery diode that is relatively slow to switch off. This necessitates adding “deadtime” delays in the control signals to account for the diode recovery, limiting the maximum switching frequency to about 20 kHz. At these lower frequencies, larger input filters and more electrolytic capacitors are required to smooth out the pulsed waveform. This results in bigger, heavier, less reliable motor drives.
GaN transistors don’t have this reverse-recovery issue, allowing them to operate at much higher switching frequencies, up to 100 kHz. This enables several advantages. First, the much higher pulse frequency means that input filters and capacitors can be made vastly smaller using ceramic capacitors instead of electrolytic ones. Ceramic capacitors have lower costs and are more reliable. Secondly, eliminating deadtime prevents motor vibrations caused by the sixth-harmonic pulsations inherent in deadtime control. This enhances motor efficiency by reducing energy lost to vibrations. Higher-frequency operation also reduces acoustic noise and EMI.
The net result is that GaN-based motor drives are significantly smaller, lighter and more reliable, and they offer higher overall system efficiency. These benefits drive the adoption of weight- and power-constrained applications like delivery drones, mobile robotics and high-performance e-bikes.
Looking ahead, GaN motor drives could enable new types of humanoid robots for warehousing and other functions by combining high torque density, compact size and extreme reliability required for these demanding, 24/7 robotic applications.
Reliability and thermal management considerations
GaN technology offers superior reliability compared with silicon-based devices. This originates from the wide bandgap and strong atomic bonds in GaN’s crystalline structure. The wider bandgap makes GaN far more damage-resistant from high temperatures and electric fields.
GaN transistors can easily withstand short-circuit conditions that would destroy a silicon MOSFET in microseconds. They also exhibit a higher tolerance for overvoltage events, with failure modes that tend to be gradual degradation rather than catastrophic failure. Manufacturers like EPC fully characterize the overvoltage capability of their GaN products.
This ruggedness makes GaN ideal for applications like motor drives, where devices may encounter transient overcurrent surges when a rotor stalls or hits an obstacle. The same resilience to extremes benefits other harsh operating conditions, such as the thermal cycles and radiation exposure experienced in space systems.
However, GaN’s increased power density also creates new thermal management challenges. GaN generates less waste heat than silicon, and that heat is concentrated in a smaller package area. Innovative cooling techniques and advanced thermal interface materials have been developed to extract heat efficiently from both sides of the compact GaN devices.
Companies like EPC provide interactive thermal modeling tools, design guides and extensive educational resources to assist engineers in overcoming these thermal challenges. The proper implementation of thermally efficient board designs and heatsinking solutions is critical to unlocking the full performance potential of GaN systems.
As GaN technology matures, its compelling advantages over traditional silicon drive widespread adoption across diverse industries. With better switching performance, higher power density, greater reliability and improved thermal characteristics, GaN is revolutionizing applications like LiDAR sensors, motor drives, power conversion and more.
While addressing new challenges in thermal management, GaN manufacturers like EPC are equipping engineers with the products, tools and knowledge to fully capitalize on this game-changing technology. As EPC’s Lidow says, the transition from silicon to GaN is as inevitable as the rising sun. Companies embracing GaN today will benefit from its unmatched capabilities and efficiency gains for years.
Learn more about GaN for motor control and LiDAR applications in a podcast featuring Lidow.
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