QR-ZVS based Secondary Side Controlled Low-Profile Adapter for USB-C PD Applications

Inhalt:
USB-C PD (Universal serial bus power delivery) adapter markets are expanding from mobile phones and laptops to many consumer products. As the market is expanding, design challenges come in terms of efficiency requirements, physical structure of the adapter, power density and wide range of operating conditions. This paper proposes a novel 65W quasi-resonant (QR) zero-voltage switching (ZVS) flyback converter developed using the state-of-the-art secondary side controller, PAG2S and its combo primaryside controller and intelligent driver, PAG2P. The PAG2S IC controls the output voltage of the flyback converter, performing synchronous rectification (SR) gate drive and power delivery (PD) control. The PAG2P is a follower of PAG2S and has a high-voltage (HV) start-up circuit. This paper elaborates the design approach of the ultra-low-profile 65W QR-ZVS form-factor board. This board also showcases the latest generation Infineon’s GaN FET that uses a lossless current sensing approach for the primary-side switch. It meets all electrical (EMI-EMC) and USB-PD compliance requirements. This adapter meets a peak efficiency of over 94%, EuP Lot6 v2 light load efficiency requirements, and a Z-height of 16 mm with power density of 26W/in(exp3).