• PF > 0.95, THD < 5%
• Support DC/AC input
• Boost Quasi-Resonant (QR) Operation
• Boost Burst Operation at Light Load
• LLC Fast Dynamic Response
• LLC Integrated Half-Bridge Driver
• Input Brown-In (BI) and Brown-Out (BO) Protection
• Boost FBB, LLC Output Overvoltage Protection (OVP)
• Cycle-by-Cycle Peak Current Protection
• Overtemperature Protection
• LLC Capacitive Mode Protection
• SOP14 package

The SY5055D PFC+LLC controller integrates a boost PFC controller and a resonant half-bridge controller.

The boost converter operates in critical conduction mode (CrM) or discontinuous conduction mode (DCM) to minimize switching losses and improve EMI performance. It uses a proprietary control method to achieve unity power factor (PF) and minimal total harmonic distortion (THD). The burst function enhances efficiency at low load conditions. The SY5055D ensures safe boost converter operation with reliable protection against output overvoltage (OVP), undervoltage (UVP), and overcurrent (OCP), as well as input brown-out (BO).

The LLC converter with proprietary control achieves a fast dynamic response and simplifies the design of loop compensation parameters. The number of external components is significantly reduced, resulting in lower BOM costs. The SY5055D ensures safe LLC converter operation with reliable protection against output overvoltage (OVP), overtemperature (OTP), and overload (OLP).