Power Integrations Expands Flyback Power with GaN for Simpler Designs Up to 450W

At APEC 2026, Bryan DeLuca spoke with Andrew Smith at the Power Integrations booth about the company’s latest TOPSwitch platform and how GaN is helping push offline flyback power supplies into higher-power applications.

For years, flyback converters have been valued for their simplicity, flexibility, and ability to support multiple outputs in offline power supply designs. But as power levels increased, designers often had to move toward more complex topologies such as LLC and half-bridge designs. At APEC 2026, Power Integrations showed how that design boundary is changing.

According to Smith, the company’s latest TOPSwitch generation adds a GaN transistor to its well-established switching technology, allowing engineers to extend flyback designs from roughly 250W up to 450W. That increase opens the door for flybacks in applications that previously required more complex architectures.

Why GaN Matters in This Design Space

The main advantage of bringing GaN into the TOPSwitch family is reduced switching loss in the primary switch. In traditional offline flyback designs, those losses become a limiting factor as power levels rise. By lowering that loss, Power Integrations is able to push the flyback topology into higher wattage ranges while keeping the overall design approach familiar and straightforward.

That matters because many engineers prefer flybacks when they can use them. They are generally easier to design, support multiple output rails well, and can reduce overall system complexity compared to other power conversion approaches.

At the booth, Power Integrations demonstrated that range with several examples, including a 60W power converter, a 160W battery charger design, and a 350W e-bike charger. Smith noted that despite the large range in output power, the basic circuit remains the same. The main differences come down to transformer size, EMI treatment, and thermal management.

Target Applications

The expanded power capability makes the design approach relevant for a broader set of products. Smith highlighted applications such as electric bicycle chargers, power tools, appliances, and industrial power supplies. These are areas where the multi-output nature of flyback designs can be especially valuable, since many industrial systems require several auxiliary voltage rails in addition to the main output.

That ability to scale from about 50W to 450W while maintaining the same basic circuit philosophy could be attractive for engineers looking to simplify product families or reuse proven design approaches across multiple power levels.

What Engineers Should Watch Closely

Smith pointed to the control loop as one of the biggest considerations when designing an offline flyback power supply. In this case, Power Integrations continues to use a simple optocoupler-based feedback approach, a method that has been widely used in power supply design for decades.

He also emphasized that synchronous rectification is not always necessary in these kinds of designs. For outputs such as 12V, 24V, or 48V, the diode losses may be low enough that adding synchronous rectification brings only limited efficiency gains while increasing complexity. In those situations, sticking with a diode can be the more practical engineering choice.

Another major design tradeoff is switching frequency. GaN devices are often associated with higher-frequency operation, but Smith cautioned that higher frequency is not always the right answer. In typical offline flyback applications, the EMI penalty from switching faster may outweigh the size reduction gained from using a smaller transformer. For that reason, the family operates around 150kHz, similar to MOSFET-based approaches, while still allowing engineers to adjust switching frequency as needed for the application.

The broader message from Power Integrations was clear: even with GaN in the design, simplicity still matters. Rather than using GaN just to chase higher switching speeds, the company is using it to increase power capability while keeping the core flyback architecture straightforward and familiar.

Simple Still Wins

For engineers designing offline power supplies, the most interesting takeaway may be that GaN is not being used here to make the system more exotic. Instead, it is being used to preserve the simplicity of flyback power conversion while stretching it into applications that once required more complicated topologies.

That combination of higher power, flexible output support, and a familiar design strategy could make this approach appealing in battery charging, industrial systems, consumer appliances, and other mid-power applications where design simplicity remains a major advantage.

For more information, visit Power Integrations.