The NE8521 offline pulse width modulation (PWM) controller adopts current mode control to achieve the application of an efficient offline single ended flyback/forward power converter. The VIN high-voltage power supply port achieves ultra-low starting current (less than 5uA), starting voltage of 20V, and undervoltage locking voltage of 7.6V. It minimizes the power consumption of the starting network under a certain starting time, and can achieve a low standby power ACDC power converter. The starting voltage of the VDD low-voltage power supply port is as low as 7.4V, which can also meet the application of low input voltage DCDC switching power supply.
The NE8521 controller operates at a fixed maximum operating frequency for PWM modulation under heavy loads. As the load is reduced to a certain extent, the controller optimizes the efficiency of the full load range by gradually simulating the frequency reduction mode, while obtaining lower light load ripple voltage and no-load power consumption without audio noise. This effectively solves the contradiction between no-load power consumption, light load ripple, and audio noise.
The NE8521 also integrates functions such as output short circuit protection, overcurrent protection, and output overvoltage protection, ensuring high reliability of the switching power supply throughout the entire range.