Power chip

The NCP1129 provides everything needed to build a reliable and compact AC-DC switching power supply with minimal peripheral components. Converters built using the NCP1129 incorporating MOSFETs with an avalanche rating of 650 V can be safely designed for international conditions without compromising overall reliability. The NCP1129 implements peak current mode control and adjustable slope compensation to ensure stability in continuous conduction mode (CCM) operation. The maximum peak current is adjustable using an external resistor, allowing designers to add slope compensation to stabilize the CCM supply. Short circuit fault conditions are detected independently from the auxiliary winding voltage, thus improving short circuit protection with true overload detection. The SOURCE pin provides access to the MOSFET source for overpower compensation. With a supply range up to 26 V, the switch also offers a dithered 65 kHz or 100 kHz switching frequency and operates under peak current mode control. When the power on the auxiliary side starts to decrease, the switch automatically folds back its switching frequency to a minimum of 26 kHz. As the power drops further, the part enters a skip cycle while limiting the peak current.

The NCP1076A and NCP1076B products integrate a fixed frequency current mode controller with 700 V MOSFETs. It has two different pin outputs, adopts very common PDIP™7 encapsulation, highly integrated, including soft start, frequency dithering, short circuit protection, skip cycle, maximum peak current set point, slope compensation and dynamic self-power supply ( No auxiliary winding required). Unlike other monolithic solutions, the NCP1076A and NCP1076B 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 automatically enters frequency foldback mode, providing excellent 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. AC input line voltage detection prevents severe runaway under low input voltage conditions (brownout) as well as over high input line (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.

High Performance Power Factor Pre-Regulator 20-SOIC -40 to 85