Zero Voltage Switching Architecture for Efficient AC/DC Flyback Converters

QuarEgg® has been designed to offer better efficiency than both active clamp and quasi resonant flyback converters, while ensuring optimized costs in line with those of quasi resonant architectures.

QuarEgg can also lower standby power consumption to less than 18mW – reducing stress on secondary side MOSFETs for lower cost and better performance – and minimize EMI thanks to very smooth transitions.

QuarEgg is implemented using an EPIC101AxQE family secondary side controller, which includes primary side driving, synchronous rectification and USB-C Power Delivery Revision 3.1.


AC/DC QuarEgg ZVS flyback converter controlled by EPIC1AFQ01 secondary side controller with integrated USB-C Power Delivery 3.1 Output

Stand-by power consumption (mW)

Stand-by power consumption: comparison between QuarEgg and top Quasi Resonant adapter
Toip QR adapter
Maximum energy efficiency in every load condition

Efficiency vs Load

Efficiency vs. output load: QuarEgg is more efficient than Quasi Resonant Flyback both at full load and in light load conditions
QuarEgg 115Vac
QuarEgg 230Vac
QR Flyback 115Vac
QR Flyback 230Vac


  • Forced Zero Voltage Switching (ZVS) under every load condition:
    • Up to 95% efficiency at full load
    • Up to 92% efficiency at light load
    • <18mW standby power consumption
  • No need for high-voltage high-side clamping MOSFET
  • Low EMI
  • Reduced voltage stress on secondary side MOSFET
  • Smaller size for up to 30W/in³ power density
  • Available output options:
    • USB Power Delivery (USB PD 3.1)
    • Fixed voltage
    • CC CV battery charger


QuarEgg evaluation boards are available -please contact your regional sales office to order evaluation boards. Customer specific prototype designs can be rapidly targeted to various power levels (e.g., 45W, 60W, 70W…) both with a primary side FET made of GaN (maximum performance) or Silicon (optimized cost vs. performance ratio).

Proprietary magnetic components designed by Eggtronic to meet customer specifications


EPIC1AFQ01 (Eggtronic Power Integrated Controller) available to control QuarEgg architectures


Best suited for low-power AC/DC power converters without PFC, to replace conventional quasi resonant and active clamp flyback converters.

Power Delivery, QuickCharge and other phone chargers and battery chargers, home assistants, small laptop chargers, tablets, loudspeakers, set top boxes...

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