The AP3981D2 is a high-performance power switcher integrated with a primary-side regulation controller and an N-channel power MOSFET. It can be used for battery charger and adaptor applications. Accurate constant voltage (CV) and constant current (CC) can be achieved without an optocoupler and secondary control circuitry.
The AP3981D2 operates in pulse frequency modulation (PFM) mode and peak current amplitude modulation (AM) mode to form a fine-tune frequency curve within the whole power range. Therefore, AP3981D2 can achieve high-average efficiency and improve audible noise.
The AP3981D2 provides comprehensive protections without additional circuitry. It contains VCC overvoltage protection, output overvoltage protection, output undervoltage protection, output short-circuit protection, cycle-by-cycle current limit, open-loop protection, and internal OTP, etc.