Optimising switching performance in SiC and GaN power designs

Sudhir Nagaraj, Director of Systems and Market Development, Allegro MicroSystems, explains that, while SiC and GaN devices support high-frequency switching, they frequently encounter system-level limitations – from bulky external bias supplies to slow protection loops – that impede optimal performance. Integration of sensing and gate driving removes these constraints to enable faster switching, improved efficiency and higher power density in applications like AI data centres and 800 V electric vehicle (EV) architectures.

As silicon carbide (SiC) and gallium nitride (GaN) devices continue their rapid adoption across electric vehicles, AI data centres and industrial power systems, the conversation is shifting. For years, the industry focused on developing and commercialising wide bandgap semiconductors capable of delivering higher efficiencies, faster switching speeds and unprecedented power density. Today, however, a new challenge has emerged: how to fully realise their potential at the system level.

According to Allegro MicroSystems, the true bottleneck no longer resides within the switches themselves. Instead, it lies in the surrounding ecosystem of current sensing, gate control, system protection and power management technologies required to operate wide bandgap devices safely and efficiently.

Speaking about the company’s latest innovations showcased at PCIM, Sudhir outlined a strategy centred on removing these system-level constraints, enabling engineers to push SiC and GaN technologies closer to their theoretical performance limits while reducing design complexity.

The system-level challenge
Wide bandgap technologies have transformed power electronics over the past decade. Both SiC and GaN devices offer significant advantages over conventional silicon, including faster switching frequencies, lower losses and higher operating temperatures. Yet faster switching creates new engineering challenges.

“The last 10 years has really been about these switches coming to life and being optimised,” explains Sudhir. “What needs to keep up is the whole system level, how to make these switches operate seamlessly, safely and optimally.”

Two technologies, in particular, have become increasingly critical: current sensing and gate drivers.

As switching frequencies climb into the hundreds of kilohertz or beyond, power systems require significantly faster visibility into current behaviour. At the same time, SiC and GaN devices are highly capable but less forgiving than legacy silicon technologies when subjected to fault conditions.

“These switches do not handle overcurrents and short circuits for long durations. You need to react within tens of nanoseconds to protect them.”

This requirement is reshaping how designers think about power conversion architectures. Effective sensing and control are no longer support functions. Instead, they are enabling technologies that determine how much performance can ultimately be extracted from the power stage.

Why current sensing has become strategic
Historically, current measurement technologies such as shunt resistors, amplifiers and Hall-effect sensors were often sufficient for power conversion systems. However, many of these solutions operate at bandwidths below 1 MHz. That creates limitations when monitoring modern wide bandgap power stages switching at dramatically higher frequencies.

Allegro’s latest current sensing technology pushes bandwidth up to 10 MHz, providing engineers with significantly greater visibility into switching behaviour. The implications extend beyond simply measuring current more accurately.

Because designers can observe current signatures in near real time and on a cycle-by-cycle basis, they gain a much deeper understanding of what is happening within the power stage. This increased visibility enables tighter control loops, more aggressive optimisation and greater confidence when operating devices closer to their performance envelope. Perhaps more importantly, higher-bandwidth sensing improves protection.

Traditional sensors may not respond quickly enough to detect overcurrent or short-circuit events before damage occurs. Wide bandgap power devices can transition from normal operation to failure in extremely short timeframes. By rapidly identifying fault conditions and communicating them to the system controller, fast current sensing helps ensure safe shutdown within the device’s operating limits.

For applications such as electrified transportation and hyperscale infrastructure, where reliability is paramount, these capabilities are increasingly becoming mandatory rather than optional.

Formula One cars need better drivers
Sudhir uses a simple analogy to describe the growing importance of gate driver technology. If SiC and GaN devices are Formula One cars, gate drivers are the drivers controlling them. The comparison is fitting. Wide bandgap switches are capable of extraordinary performance, but extracting that performance safely requires intelligent control. Driving devices too aggressively can trigger electromagnetic interference (EMI), excessive ringing and voltage overshoot. Drive them too conservatively and efficiency suffers while thermal losses increase. The challenge lies in finding the optimal balance.

Traditionally, this balance was established using fixed passive components such as gate resistors. Once selected, these hardware-based parameters remained fixed regardless of changing operating conditions. That approach becomes increasingly limiting as power systems grow more dynamic.

To address this challenge, Allegro has demonstrated software-defined gate control using SPI-based configuration methods. Rather than relying solely on fixed hardware parameters, engineers can dynamically adjust gate drive characteristics in response to changing operating conditions. This flexibility enables systems to switch faster when performance demands increase while simultaneously adapting to temperature shifts, changing loads or evolving operating environments. The result is a more intelligent power stage capable of optimising efficiency, reliability and safety in real time.

Eliminating the hidden complexity of isolation
One of Allegro’s most notable PCIM demonstrations focused on its Power-Thru isolated gate driver architecture.

In conventional designs, isolated gate drivers typically require separate isolated bias supplies. Designing these supplies can add considerable complexity, particularly in multi-level architectures containing numerous high-side switches. While engineers want to focus on power conversion challenges, they often find themselves dedicating significant development effort to isolated power design. Integrating isolated power directly into the gate driver fundamentally changes that equation.

According to Sudhir, customer feedback has been overwhelmingly positive because the approach removes a layer of complexity that many power electronics designers would prefer not to manage.

Beyond simplifying development, the architecture also delivers significant space savings. By eliminating transformers and associated support components, designers can reduce board area while simplifying layouts. For applications where power density has become a primary competitive advantage, those savings can be substantial.

Real-time visibility changes everything
One recurring theme throughout the discussion is the importance of visibility.

Many engineers, Sudhir argues, still approach wide bandgap systems using assumptions developed during decades of conventional silicon design. A common misconception is that faster switches can simply be driven harder to maximise performance. In reality, switching speed must be carefully controlled. Excessive switching aggressiveness can introduce EMI problems and reliability concerns, while insufficient speed undermines efficiency gains.

Another misconception relates to sensing latency. Many legacy architectures effectively provide historical information, forcing controllers to make decisions based on switching events that occurred several cycles earlier. High-speed current sensing changes that paradigm. Instead of reacting to old data, controllers can respond to conditions occurring within the current switching cycle. This creates opportunities for more intelligent decision making, improved protection strategies and more aggressive optimisation techniques.

As power densities continue rising, real-time awareness may become one of the most valuable assets available to system designers.

AI data centres and 800 V architectures
Few markets illustrate these trends more clearly than AI infrastructure.

The explosive growth of AI workloads is driving unprecedented power demands in data centres, forcing operators to rethink electrical architectures throughout the facility.

One notable development is the industry’s growing interest in 800 V distribution architectures. Interestingly, Allegro sees strong parallels between data centres and electric vehicles. Both sectors are attempting to move large amounts of power through increasingly compact systems. Both require exceptional efficiency. Both are embracing higher voltage architectures to minimise losses and improve power density. And both increasingly rely on many of the same enabling technologies.

“AI data centres and EVs are not too different in the challenges they are facing,” Sudhir notes.

In both markets, fast sensing and intelligent gate control help enable higher switching frequencies, more compact power conversion systems and improved efficiency. These advantages have become particularly valuable as operators attempt to balance power availability, cooling constraints and total cost of ownership. For data centres, where operational energy expenses often exceed initial hardware costs over the life of a facility, incremental efficiency gains can translate into substantial economic benefits.

The importance of the ecosystem
As power electronics becomes increasingly sophisticated, no single supplier can optimise the entire system alone. Sudhir emphasises that ecosystem partnerships have become critically important for accelerating adoption. Collaborations with transformer providers, SiC and GaN manufacturers, passive component companies and system developers enable joint optimisation across the complete power chain. The result is a growing portfolio of validated reference designs that reduce risk for customers. That confidence matters.

Engineers are rewarded for minimising risk, shortening development cycles and delivering products to market quickly. Proven ecosystem solutions help satisfy all three objectives. By validating interactions between sensors, gate drivers, switches and passive components before customers begin development, ecosystem partnerships effectively reduce uncertainty and accelerate deployment. As wide bandgap technologies enter mainstream markets, this collaborative approach may become increasingly important.

Rethinking legacy designs
Despite the advantages of integrated solutions, many engineers continue to rely on familiar architectures. Sudhir understands the hesitation. Legacy approaches are proven, well-understood and perceived as lower risk. However, the company warns against evaluating technology decisions solely through a near-term lens.

Power electronics platforms often require years to progress from initial design through validation and commercial deployment. By the time a system reaches production, market requirements may have evolved substantially. This is especially true in rapidly moving sectors such as electric transportation and AI infrastructure.

According to Sudhir, engineers must evaluate technologies according to long-term system benefits rather than immediate component costs alone.

The broader economics frequently favour wide bandgap adoption. Higher efficiency reduces energy consumption. Improved power density lowers material requirements. Better thermal performance simplifies cooling strategies.

Collectively, these system-level gains can outweigh any initial increase in component cost. In data centres, where total cost of ownership remains a defining metric, the financial impact of better efficiency alone can be significant over an installation’s lifetime.

Integration comes to the wheel end
While Allegro’s PCIM demonstrations focused heavily on power conversion, the company has also been advancing integration within automotive electronics.

Its recently introduced A81415 PMIC combines power management and wheel-speed sensor functionality within a single ASIL-D safety architecture. The innovation reflects the automotive industry’s migration toward zonal and distributed vehicle architectures.

In modern brake-by-wire systems, intelligence is increasingly moving closer to the wheel itself. Controllers, power management devices and sensing elements must operate within a highly constrained environment characterised by vibration, heat, electrical stress and severe space limitations. By integrating wheel-speed sensing functionality directly into the PMIC, Allegro eliminates up to nine external components and reduces PCB area by more than 50%.

The approach removes discrete wheel-speed sensor interfaces, decoders, level shifters and associated support circuitry while simplifying overall system architecture. For automotive engineers, the benefits extend beyond space savings. Fewer components reduce potential failure points, simplify qualification processes and accelerate development cycles. In safety-critical systems such as braking, these advantages carry particular importance.

Preparing for software-defined vehicles
Component consolidation is becoming increasingly important as automotive manufacturers transition toward software-defined vehicle architectures. Integrated solutions provide several benefits simultaneously.

They reduce system weight and complexity while simplifying compliance processes and improving reliability. They also allow engineering teams to focus on higher-level system functions rather than managing interactions between numerous discrete devices.

According to Sudhir, every additional component represents another potential point of failure. Carefully integrating functionality while maintaining safety and redundancy therefore becomes an important strategy for improving system robustness.

The company’s latest automotive developments also acknowledge the industry’s gradual transition toward 48 V electrical architectures. Although the new PMIC is optimised for 12 V operation, it has been designed to work seamlessly alongside Allegro’s complementary 48 V-to-12 V conversion technologies, creating a migration path for future brake-by-wire platforms.

Looking ahead: Intelligence at the edge
Looking beyond today’s products, Allegro’s roadmap points toward increasing intelligence within both sensing and gate control technologies.

Future sensors, according to Sudhir, will do more than measure current.

They will help identify patterns, detect anomalies and potentially recognise conditions associated with impending failures before problems occur. This evolution aligns closely with broader trends toward predictive maintenance and intelligent power management.

Similarly, future gate drivers are expected to become increasingly adaptive, enabling faster reactions, more precise switching behaviour and higher system efficiency. These capabilities may prove especially important as emerging applications such as physical AI continue to gain momentum.

Robotic and autonomous systems introduce unique requirements around size, efficiency and noise immunity. Components must fit into increasingly constrained mechanical spaces while delivering high currents and operating reliably despite dense electronic integration.

For Allegro, these trends create opportunities to build on its core strengths in sensing, control and power management.

The company believes the future of power electronics will not be defined solely by better switches. Instead, success will increasingly depend on the intelligence surrounding those switches.

As SiC and GaN devices continue to mature, the competitive battleground is shifting from semiconductor performance alone to system optimisation. Faster sensing, adaptive gate control, integrated architectures and collaborative ecosystem development are becoming the critical technologies that determine who can unlock the full promise of wide bandgap power.

In that sense, the next chapter of power electronics may not be about building a faster Formula One car. It may be about creating a smarter driver.