Flyback architecture “significantly reduces” low power AC/DC losses
Efficiency above 94 per cent and a reduced bill of materials compared to conventional techniques is available using Eggtronic’s QuarEgg primary side regulation (PSR) flyback solution.
The low component count fixed-output AC/DC converter reference design is designed for applications operating at powers below 120W is claimed to significantly improve the efficiency and reduce the size of AC/DC converters that would traditionally have used active clamp flyback (ACF) and quasi-resonant (QR) topologies.
Built around Eggtronic’s patented forced zero voltage switching (ZVS) architecture, QuarEgg PSR delivers a very flat idle-to-full-load efficiency curve ranging from 91 per cent at low load to over 94.5 per cent at maximum power. By using the architecture, designers can significantly reduce total operational losses when compared to conventional ACF and QR techniques, said the company.
It uses Eggtronic’s EPIC QuarEgg PSR 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 integrated, miniature 5.0 x 5.0mm device incorporates an optimised low power mode for enhancing performance at zero and light loads. It also provides built-in protection against over-voltage, over-current, brownout and extreme temperatures.
Igor Spinella, Eggtronic’s CEO and founder, said the QuarEgg forced ZVS concept provides engineers with a solution that enables high-efficiency low- to high-load operation while reducing overall component count. “In our first iteration we created a PD concept that eliminated the need for a high-voltage, high-side clamping MOSFET, and now we have extended this concept to fixed-voltage solutions that allow us to place an EPIC controller on the primary side and further drive down BoM [bill of materials],” he said.
Target applications for QuarEgg PSR include routers, set-top-boxes, white goods and other low-power applications where efficiency and power density are key criteria but power factor correction (PFC) is not required.