NCP1937A3DR2G

The NCP1937A3DR2G from ON Semiconductor is a combination Power Factor Correction (PFC) and Quasi-Resonant Flyback controller IC. It is designed to implement compact and highly efficient Switched Mode Power Supplies for adapter applications.

This device integrates PFC functionality that exhibits near-unity power factor while operating in Critical Conduction Mode (CrM) with a maximum frequency clamp. The quasi-resonant current-mode flyback stage includes proprietary valley-lockout circuitry for stable valley switching. It operates down to the 4th valley and toggles to a frequency foldback mode with a minimum frequency clamp to eliminate audible noise. Skip mode operation ensures excellent efficiency in light load conditions with very low standby power consumption.

Common features include a wide VCC range from 9 V to 30 V with built-in overvoltage protection, high-voltage startup, and active input filter capacitor discharge circuitry for reduced standby power. It also has an integrated high-voltage brown-out detector and a high-voltage switch that disconnects the PFC feedback resistor divider to further reduce standby power. The fault input is NTC compatible with latch and auto-recovery options. It includes 0.5 A / 0.8 A source/sink gate drivers and internal temperature shutdown. A power savings mode reduces supply current consumption to enable very low input power applications.

The NCP1937A3DR2G is available in a 20-SOIC package and is suitable for surface mounting. It operates within an ambient temperature range of -40°C to 125°C.