The IRIS4009(K) is a dual mode voltage and current controller combined with a MOSFET in a single package. The IRIS4009(K) is designed for use in universal and single input AC/DC and DC/DC switching power supplies and is capable of powers up to 30W for a universal line input. The device can operate in either a quasi-resonant or Pulse Ratio Control (PRC) mode, and thereby variable frequency operation.