Power electronics evolve to maximize efficiency

Following the introduction of Industry 4.0, power electronics are becoming more significant in both digital and industrial infrastructures. Factories, energy systems, and data centers are getting smarter and more connected. This requires efficient power solutions that offer high power density and can scale with them.

Semiconductors are expected to deliver performance beyond the limits of conventional silicon-based power devices. Wide-bandgap (WBG) materials such as silicon carbide (SiC) and gallium nitride (GaN), as well as novel approaches to designing, packaging, and controlling power devices, are helping achieve the main goals of Industry 4.0: efficiency, flexibility, scalability, and intelligence.

800-VDC power architecture

One of the most significant changes introduced in the power system is the move of data centers to 800-VDC distribution, as detailed in an Nvidia white paper. Traditional systems that use AC and low-voltage DC can’t keep up with the speed and growth needs of AI-based workloads. High-performance computing clusters, especially those that support generative AI and machine learning, demand more power and should use it as efficiently as possible.

By raising the distribution voltage to 800 VDC, operators can reduce the current for a given power level. This approach offers the benefits of reduced I²R losses and the ability to use thinner wires. Overall, efficiency can thus be increased, and more power can be integrated in the same area or volume. The design also becomes less complicated because there are fewer steps in the conversion process.

This new architecture directly affects semiconductor requirements. Power devices need to perform well at higher voltages with minimum loss and support fast switching. Chipmakers and manufacturers are developing power solutions to support Nvidia’s 800-VDC power architecture reference design for next-generation AI factories to improve efficiency and reduce power losses.

To support gigawatt-scale AI factories based on an 800-VDC power architecture, Flex, for example, introduced a new reference design (Figure 1) that integrates power, liquid cooling, and compute capabilities into a modular assembly. This prefabricated solution streamlines the implementation of 800-VDC architectures and, according to the company, enables 30% faster deployment than conventional systems.

SiC semiconductor advances

Due to its physical properties, such as high breakdown voltage, low switching losses, and high thermal conductivity, SiC can operate efficiently and provide high reliability in high-voltage and high-power environments.

At the high-voltage end, SiC devices are going into the multi-kilovolt range. More devices are gaining ratings above 1,200 V, making SiC more common in places where silicon-based power devices used to be the norm.

Navitas Semiconductor recently announced the availability of samples for its 2,300-V and 3,300-V high-voltage SiC products, specifically designed to increase efficiency in AI data centers, power grids, and renewable energy infrastructure. The devices, available in discrete, module, and known-good-die formats, are based on the company’s Trench-Assisted Planar architecture.

This semiconductor structure optimizes electric-field management, significantly reducing voltage stress and improving avalanche robustness compared with traditional trench- or planar-MOSFET designs. It also achieves lower R_DS(on) at high temperatures and better current spreading.

As power devices improve, their packaging becomes increasingly crucial to the overall performance of the system. Newer packages are designed to reduce parasitic inductance, improve thermal management, and handle larger current densities.

These advancements in packaging technology enable higher performance and efficiency gains. Texas Instruments (TI), for example, recently unveiled two isolated power modules for applications from data centers to electric vehicles that require improvements in power density, efficiency, and safety. The UCC34141-Q1 and UCC33420 isolated power modules leverage TI’s IsoShield technology, which copackages a high-performance planar transformer and an isolated power stage, providing functional, basic, and reinforced isolation capabilities.

TI’s proprietary multichip packaging solution claims up to 3× higher power density than discrete solutions in isolated power designs and shrinks the solution size by as much as 70% by packing more power into smaller spaces. Applications range from factory automation PLC modules and EV and powertrain systems to grid infrastructure and rack and server power.

Wolfspeed Inc. has revealed that its 300-mm SiC platform, leveraging patent-pending innovations, is set to become a key material component for AI and high-performance computing (HPC) packaging by the late 2020s. Figure 2 shows a conceptual demonstration of an interposer substrate built on the company’s 300-mm SiC wafer. According to Wolfspeed, the SiC substrate helps to improve the thermal, mechanical, and electrical performance of next-generation packaging structures required by AI and HPC systems.

GaN advances

While SiC excels at high voltages, GaN is suited for low- and medium-voltage applications, especially below 650 V. This semiconductor can switch at high frequencies, up to the megahertz range, with very low power loss, making power converters more efficient and smaller and requiring less cooling.

One important trend in GaN’s growth is integration. For example, Schottky diodes could be incorporated into GaN transistors to reduce losses from reverse conduction and make it easier to build power stages. Following this concept, Infineon Technologies AG has introduced the industry’s first industrial-grade GaN power transistors featuring an integrated Schottky diode.

Traditionally, GaN devices in hard-switching applications suffer from higher power losses due to their large body-diode voltage drop. This issue gets worse during the “deadtime” of a power controller. Engineers previously solved this by adding an external Schottky diode or complex controller tuning, both of which increase design time and costs. The new CoolGaN transistor G5 family solves this by integrating the diode directly into the transistor, reducing deadtime losses and boosting overall system efficiency.

Another important trend is bidirectional switching, where new GaN devices can block current and voltage in both directions. This simplifies converter topologies and requires fewer components. This capability is especially crucial for applications such as energy storage systems, EV chargers, and power-factor-correction circuits.

Renesas Electronics Corp. has introduced the industry’s first bidirectional switch (TP65B110HRU) based on depletion-mode (d-mode) GaN technology (Figure 3). Most current high-power conversion systems rely on unidirectional silicon or SiC switches that block current in only one direction. This limitation forces engineers to design multi-stage circuits or use “back-to-back” switch configurations, which significantly increases component count and reduces overall efficiency.

By integrating bidirectional blocking into one GaN product, this technology enables “single-stage” power conversion. The high switching speed and low stored charge of GaN also enable higher power density and switching frequencies. According to the company, this architecture has demonstrated over 97.5% power efficiency, providing a solution well-suited for AI data centers, on-board EV chargers, and renewable energy applications.

Solid-state transformers

Solid-state transformers (SSTs) are a huge change in how power is transferred and controlled. SSTs are not like ordinary transformers, as they use power electronic converters to modify, split, and control the voltage.

Using this technology, more advanced features become available. These include two-way power flow, real-time voltage management, and the capacity to operate with renewable energy sources. Smart grids, microgrids, and Industry 4.0 all need SSTs that can change rapidly and easily. For SSTs to grow, WBG semiconductors are particularly significant.

For example, Infineon and DG Matrix, a company specializing in SSTs, have partnered to integrate SiC semiconductors into the Interport multiport SST platform. This collaboration aims to modernize the connection between the public grid and energy-intensive applications such as AI data centers, EV charging, and industrial microgrids.

Unlike traditional copper- and iron-based transformers, SSTs are semiconductor-based devices. They are smaller and lighter, accelerating deployment and providing higher power density. Adopting Infineon’s SiC technology, these SST systems achieve improved efficiency and reliability.

The technology enables direct power conversion from medium-voltage grid levels to the low-voltage requirements of modern digital infrastructure. DG Matrix plans to scale toward higher-voltage platforms to support the global rollout of high-performance power infrastructure.

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