The UCC256304 is a fully featured LLC controller with integrated high-voltage gatedriver. It has been designed to pair with a PFC stage to provide a complete power system using aminimum of external components. The resulting power system is designed to meet the most stringentrequirements for standby power without the need for a separate standby power converter.UCC256304uses hybrid hysteretic control to provide best in class line and load transient response. Thecontrol makes the open loop transfer function a first order system so that it’s very easy tocompensate and is always stable with proper frequency compensation.
The UCC256304 is unique in that the controller is able to operate over a large DC inputrange. This is accomplished by making the input overvoltage sense threshold much larger than theinput voltage start threshold. This allows the LLC to startup and enter a low power standby modewithout the need to enable the PFC and enables the LLC to accommodate an extensive range of commonAC inputs.
UCC256304 provides a highly efficient burst mode with consistent burst power level duringeach burst on cycle. The burst power level is programmable and adaptively changes with inputvoltage.