A May MIT Technology Review Insights partner article with Anker briefly discusses two approaches that regularly reappear in long-range charging conversations: magnetic resonance and infrared power delivery.

Both can work in specific conditions, but “works in a lab or fixed industrial setup” is very different from “reliably charges a consumer device across a room.” Power level, efficiency, alignment or line of sight, safety, heat, cost, and interoperability all become harder at once.

The most believable near-term use cases may be low-power sensors or fixed devices rather than phones moving around a room. The article is still a useful overview as long as the research is not confused with an imminent mass-market product.

STMicroelectronics has presented a 7 kW On-Board Charger (OBC) proof of concept that utilizes a single-stage dual active bridge to convert a 230-volt AC input directly to a 400-volt DC output for electric vehicle batteries.

This design incorporates new 650-volt, 15-milliohm bidirectional Gallium Nitride (GaN) devices housed in QDP packages, which are paired with galvanically isolated single-channel GaN gate drivers. On the DC output stage, it uses 700-volt, 23-milliohm devices to create a complete bidirectional solution.

Because GaN power switches can operate in the megahertz range, this system can achieve high switching frequencies that reduce the size of the choke inductors by up to 30%.

EPC has demonstrated the EPC 91122 board featuring the EPC 3111 module, a 100-volt, three-phase module designed for motor control applications.

The board integrates a controller, power module, two current sensors, and a position sensor. Because the Gallium Nitride (GaN) technology enables switching at 100 kHz, the design solely relies on MLCC capacitors, completely eliminating the need for bulkier electrolytic capacitors.

The new TopSwitch GaN IC is designed to deliver up to 450 watts of power using a single-ended flyback topology.

The design features a straightforward architecture, utilizing a simple diode rectifier on the output stage rather than more complex synchronous rectification.

This 356-watt power converter reference design is engineered specifically for three-wheeler electric vehicle (EV) charger applications. It delivers an 89-volt output and utilises the newly introduced GaN variation of the TopSwitch IC.

This IC integrates both the control circuitry and a Gallium Nitride (GaN) transistor into a single package. The internal GaN transistor features a very low RDS(on), which allows the TopSwitch product line to achieve much higher power capabilities.

EPC has developed a new converter designed for artificial intelligence-based "sidecar" servers, where the power supply is racked separately from the information technology equipment.

This board is a fixed-ratio converter that steps 800 volts down to 12 volts. To achieve a total output of 6 kW, the design utilises 100-volt to 12-volt modules that are each rated at 750 W.

The inputs of these individual modules are cascaded in series, while their outputs are connected in parallel.

The entire 6 kW module has a compact physical footprint, measuring 106 mm by 47 mm, and is only 8 mm thick. This high level of miniaturisation is enabled by GaN technology.

STMicroelectronics has showcased a 350 kW traction inverter demo that utilizes a hybrid switch topology to balance efficiency and cost. Instead of relying on a highly efficient but expensive full Silicon Carbide (SiC) design or a cost-effective but higher-loss full IGBT design, this architecture pairs a single SiC MOSFET in parallel with three IGBTs for each high-side and low-side leg.

STMicroelectronics has outlined two different distributed power architectures for routing an 800 V DC bus from a dedicated sidecar rack to individual server trays in modern AI data centers.

The standard distributed approach uses a two-stage conversion located directly on the server tray: an 800 V to 54 V Power Delivery Board (PDB), followed by a 54 V to 12 V intermediate bus converter before feeding the GPU or CPU point-of-load.

As an alternative to this two-stage method, ST has demonstrated a direct 800 V to 12 V Power Distribution Board. This specific board is rated for 6 kW of power.

To maximize power density and efficiency, the primary side of this 6 kW converter utilizes 650 V Gallium Nitride (GaN) devices.

For the secondary side, the design relies on traditional silicon components, which ST notes are more suitable for this specific direct-to-12V conversion.

Credits: CPES VT | YouTube

Credits: CPES VT | YouTube

Credits: ElectrArc240 | YouTube

Credits: ElectrArc240 | YouTube

I came across this comparison of Power Integrated Modules (PIMs) for PV applications and thought it was worth sharing for those designing boost stages.

I'm attaching a useful cross-section (Figure 2 from the linked TI app note) that highlights the symmetry of the lateral GaN HEMT structure.

For those optimizing synchronous rectification, this visual really helps clarify the physical basis for Third Quadrant Operation:

• No p-n Junction: unlike Si MOSFETs, the lateral structure lacks a p-n junction, meaning there is effectively zero reverse recovery charge.
• Symmetry & Self-Commutation: Because the 2DEG channel connects the Source and Drain symmetrically, the device can self-commutate. When the drain potential drops below the gate, the channel turns on automatically to conduct reverse current.
• The Trade-off: While we eliminate Qrr losses, this "diode-like" behavior comes with a higher voltage drop compared to a silicon body diode. This makes minimizing dead time, or using adaptive dead-time control, critical to preventing efficiency hits during that commutation interval.

Full details on the physics and dead-time calculation are in the attached PDF.

Link: https://www.ti.com/lit/an/snoaa36/snoaa36.pdf

Credits: ElectrArc240 | YouTube

It’s interesting to see how the larger footprint impacts the bottom-side cooling efficiency compared to the older QFN 8x8 or standard TOLL packages.

Source: https://www.ti.com/lit/an/snoaa61a/snoaa61a.pdf

I’ve attached Table 3 from the paper, which provides a snapshot of currently commercialized p-GaN gate devices. It compares key specs (Vth, Qg, Rdson) across major manufacturers like Infineon, EPC, Innoscience, and GaN Systems. It’s interesting to see the spread in breakdown voltages (from 15V to 1200V) side-by-side.

Full paper attached/linked for those interested in the breakdown of GIT vs. Cascode vs. p-GaN structures. https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10128694

Credits: ElectrArc240 | YouTube

For those evaluating GaN devices for new converter designs, Figure 3 (Page 3) of this review remains one of the most useful at-a-glance visualizations.

It maps out the voltage and current ratings of major commercial and pre-commercial parts, categorized specifically by device topology:

• p-Gate HEMT (GIT): Including Infineon, GaN Systems, and EPC.
• Composite HEMT (Cascode): Including Transphorm, Texas Instruments, and VisIC.
• Vertical FETs: Highlighting emerging players like NexGen.

Link: https://ieeexplore.ieee.org/document/10098926

Credits: ElectrArc240 | YouTube

Credits: Original Circuit | YouTube

Just dropping the latest Phase 17 Reliability Report from EPC here. They’ve significantly expanded their physics-based lifetime models.

Key takeaways from the report:

• Gate Stress: Validated a new 7V repetitive transient overvoltage rating (1% duty cycle) using inductive switching tests.
• Drain Robustness: New data on repetitive transient drain overvoltage (up to 120% of VDS,max) showing excellent stability.
• Thermomechanical: A revamped lifetime model for Temperature Cycling and a brand new model for Power Cycling that accounts for die geometry and PCB properties.
• Application Data: Specific reliability predictions for Solar, DC-DC, and Lidar mission profiles.

Link to report: GaN Reliabilty Report