Power chip

The NCP4304A/B is a full-featured controller and driver specifically designed to control synchronous rectification circuits in switch-mode power supplies. Due to its versatility, it can be used in various topologies such as flyback, forward and half-bridge resonant LLC. The combination of externally adjustable minimum switching times helps resist ringing from PCB layout and other parasitic elements. As a result, reliable and noise-free operation of the SR system is guaranteed. The extremely short turn-off delay time, the high current sink capability of the driver and the automatic encapsulation parasitic inductance compensation system can maximize the synchronous rectification MOSFET conduction time and further improve the energy efficiency of SMPS. Finally, the wide operating VCC range combined with two versions of the driver voltage clamp simplifies the implementation of the SR system in 24 V output applications.

The NCP1077A and NCP1077B products integrate a fixed frequency current mode controller with 700 V MOSFETs. It uses two different pin outputs of the very common PDIP™7 encapsulation, which provides a high degree of integration, including soft start, frequency dithering, short circuit protection, cycle skipping, maximum peak current set point, slope compensation and dynamic self-power supply ( No auxiliary winding required). Unlike other monolithic solutions, the NCP1077A and NCP1077B are noiseless: during normal load operation, the part switches at a usable frequency (65 or 100 kHz). When the demand for output power disappears, the IC will automatically enter frequency foldback mode, providing excellent energy efficiency at light loads. When power demand decreases further, it enters skip mode, reducing standby power consumption to no-load conditions. Protection features include: timers to detect overload or short circuit events, overvoltage protection with automatic recovery. Input line voltage detection prevents severe runaway under low input voltage conditions (undervoltage) as well as over high input lines (AC line overvoltage protection). This also enables the overpower protection to compensate for any internal delays at high input voltage conditions, optimizing the maximum output current capability. To improve standby performance, connecting an auxiliary winding stops DSS operation, helping to reduce input power consumption on the high line to less than 50 mW.

Low Power Economical BiCMOS Current Mode PWM 8-SOIC -40 to 85

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