NCP1342 Quasi-Resonant Flyback Controller with Valley Lock-Out Switching

onsemi's NCP1342 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 NCP1342 can enable no-load power consumption below 30 mW. Featuring proprietary valley-lockout circuitry, ensuring stable valley switching, this system works down to the 6^th valley and transitions to frequency foldback mode to reduce switching losses. As the load decreases further, the NCP1342 enters quiet-skip mode to manage the power delivery while minimizing acoustic noise.

To ensure light load performance with high-frequency designs, the NCP1342 incorporates minimum peak current modulation (MPCM) to reduce the switching frequency quickly. To help ensure converter ruggedness, the NCP1342 implements several key protective features such as internal brownout detection, a non-dissipative over-power protection (OPP) for constant maximum output power regardless of input voltage, a latched overvoltage and NTC-ready over temperature protection through a dedicated pin, and line removal detection to safely discharge the X2 capacitors when the AC line is removed.

Resources

• Design Note DN05126-D: High-Efficiency QR Flyback Adapter with USB-PD/Type-C Output Utilizing NCP1342
• Design Note DN05115-D: 90 W Type-C PD3.0/QC4.0 Power Adapter Solution with WT6615F
• Design Note DN05105-D: 30 W Type-C PD3.0/QC3.0 Power Adapter Solution with WT6632F
• Test Procedure for NCP1342PD65WGEVB