High Voltage Switching Regulator for Offline SMPS

The NCP1126 products integrates a fixed−frequency peak current mode controller with a low on− resistance high voltage, 650 V MOSFET. Available in a PDIP−7 package, the NCP1126 offers a high level of integration, including soft−start, frequency−jittering, short−circuit protection, thermal shutdown protection, frequency foldback mode and skip−cycle to reduce power consumption in light load condition, peak current mode control with adjustable internal ramp compensation and adjustable peak current set point. During nominal load operation, the part switches at one of the available frequencies (65 or 100 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 no load condition. Protection feature include: a timer to detect an overload or a short−circuit event with auto−recovery or latch protection, and a built−in VCC overvoltage protection.The switcher also provides a jittered 65 kHz or 100 kHz switching frequency to improve the EMI.