Secondary Side-Controlled Fly-Back Converter for USB PD Charger Application

Universal serial bus power delivery (USB-PD) charg-ers are gaining popularity due to their versatility. However, these chargers have design challenges such as high-power density, full and light load efficiencies and tight regulations across a wide input and output voltage range as per PD specifications. This paper proposes a novel secondary side-controlled fly-back converter approach using PAG2S and PAG2P ICs from Infineon Technologies. The architecture integrates three key functions for PD chargers using just two ICs, whereas state of the art solution requires 3 ICs to achieve these functions. This paper presents the architecture of a PD charger using the unique combination of PAG2P and PAG2S ICs, suitable for all high efficiency fly-back configurations like Active clamp fly-back (ACF), Quasi resonance zero voltage switching (QR ZVS), and Quasi resonance (QR). A PAG2S and PAG2P based 65W charger with Cool GaN FET and ACF topology is used to demonstrate the advantage of integration, achieving a high power density of 32. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5\mathrm{W}/\text{inch}^{3}$</tex> for Printed Circuit Board Assembly (PCBA), peak efficiency of over 94.5 %, and EuP lot6 v2 compliance for light load efficiency