The NCP1000 through NCP1002 series of integrated switching regulators, combine a fixed frequency PWM controller with an integrated high voltage power switch circuit. This chip allows for simple design and minimal parts count for very low cost applications which utilize an ac input. This chip is designed to power a single ended topology, typically a discontinuous mode flyback, with secondary side sensing. The internal high voltage switch circuit and startup circuit can function in continuous operation over a wide range of inputs, from 85 Vac to 265 Vac, and thus can be used in any existing power system in the world. Though inexpensive, these devices include a number of features such as undervoltage lockout, over-temperature protection, bandgap reference and leading edge blanking that make them an excellent value.