NCP1071: High-Voltage Switcher for Low Power Offline SMPS

The NCP1071 integrate a fixed frequency current mode controller with a 700 V MOSFET. Available in a PDIP−7 or SOT−223 package, the NCP1071 offers a high level of integration, including soft−start, frequency−jittering, short−circuit protection, skip−cycle, a maximum peak current set point, ramp compensation, and a Dynamic Self−Supply (eliminating the need for an auxiliary winding). Unlike other monolithic solutions, the NCP1071 is quiet by nature: during nominal load operation, the part switches at one of the available frequencies (65, 100 or 130 kHz). When the output power demand diminishes, the IC automatically enters frequency foldback mode and provides excellent efficiency at light loads. When the power demand reduces further, it enters into a skip mode to reduce the standby consumption down to a no load condition. Protection features include: a timer to detect an overload or a short−circuit event, Overvoltage Protection with auto−recovery and AC input line voltage detection. For improved standby performance, the connection of an auxiliary winding stops the DSS operation and helps to reduce input power consumption below 50 mW at high line.