DN05089/D, High Efficiency, <30mW Standby QR Adapter Design Note

DN05089/D, Design Note for the NCP1340 is a highly-integrated quasi-resonant flyback controller suitable for designing high-performance off-line power converters. With an integrated active X2 capacitor discharge feature, the NCP1340 enables no-load power consumption below 30 mW. The quasi-resonant operating mode features a proprietary valley-lockout circuitry ensuring stable valley switching down the 6th valley. After the 6th valley the controller transitions to a frequency foldback mode to reduce switching losses in lighter load conditions. As the load continues to decrease the NCP1340 will enter a Quiet-Skip mode to efficiently manage power delivery while minimizing acoustic noise. Secondary side synchronous rectification (SR) is implemented with the NCP43080 for optimized efficiency across all operating modes