Ultra-high-efficiency AC/DC ZVS flyback architecture unveiled

Update: April 3, 2024

Eggtronic has unveiled a new addition to its ‘QuarEgg’ ZVS Flyback family of high-density power conversion solutions. This ultra-high-efficiency architecture increases the power output available to designers before they are required to implement PFC.

European standard EN61000-3-2 dictates that PFC is required for any power supply rated above 75W. This has resulted in a market dominated by 65W AC/DC converters to ensure less than 75W is consumed from the mains input. With the latest evolution of the QuarEgg, engineers can develop solutions that support 70W, making non-PFC designs available to applications that might previously have required correction.

Built around its patented and proven low-loss, forced ZVS flyback architecture, the new 70W version of QuarEgg delivers efficiencies of over 94.5% across the full no-load to full-load range. This efficiency is even achieved with a combination of a low 90V input voltage and a full load, which is typically the ‘worst-case scenario’ for an SMPS.

Using the architecture, designers can significantly reduce total operational losses compared to conventional ACF and QR topologies, simplify overall circuit design and thermal management, and reduce component count, form factor, and cost.

“Integrating PFC into a design increases complexity, component count and size, three things that OEMs look to minimise wherever possible,” says Igor Spinella, Eggtronic’s CEO and founder. “To date, designers have had to choose 65W technologies and sacrifice efficiency for cost with QR topologies or spend more to obtain the higher efficiencies of ACF. Now, by creating a 70W version of our proven QuarEgg forced ZVS AC/DC architecture, we are opening up the possibility of PFC-free designs to higher powers than previously possible using the best ACF architectures, with smaller form factors and at costs that are comparable with QR alternatives.”

At the heart of the latest QuarEgg development is the company’s EPIC QuarEgg IC, a mixed-signal, low-power controller with multi-mode operation and synchronous rectification control that provides all the necessary primary side regulation without the need for an optocoupler. This highly integrated, miniature 5mm x 5mm device incorporates an optimised low-power mode for enhancing performance at zero and light loads and provides built-in protection against overvoltage, overcurrent, brownout and extreme temperatures.

The company has built a demonstration of the new QuarEgg technology, which provides 70W output power in a form factor of just 72.6mm x 39.1mm x 17.5mm. The architecture will allow for smaller form factors, and target applications will include chargers for portable equipment, set-top boxes, routers and Bluetooth speakers, IoT and small consumer devices, and high-brightness LED lamps.