onsemi (Ansemi)

SOIC-16

taping

2500

The NCP1631 controller is used in a 2-phase interleaved power factor correction pre-converter. Interleaving consists of two small stages connected in parallel, instead of one large stage. This approach has several advantages, such as simple implementation, the ability to use smaller components, and better heat dissipation. These properties make this interleaved PFC topology suitable for thin applications such as flat-panel TVs and adapters for ultra-thin notebooks. Interleaving can also be extended to the power range of critical conduction mode of operation which is energy efficient and cost effective (no need for low trr diodes). The NCP1631 operates in Frequency Clamped Critical Conduction Mode (FcCrM). This circuit uses frequency foldback to linearly reduce the clamped frequency as a function of power. Therefore, the NCP1631 provides optimized energy efficiency over the entire load range. In addition, the NCP1631 driver has a 180 phase shift which greatly reduces the current ripple, thus reducing EMI and reducing the rms current in the bulk capacitor. The NCP1631 combines all the functions required to build a robust and compact interleaved PFC stage with a minimal number of external components. Using SOIC-16 encapsulation.