The AP1680 is a high performance AC/DC power supply controller for LED drivers, battery charger and adapter applications. The device uses Pulse Frequency Modulation (PFM) method to build discontinuous conduction mode (DCM) flyback power supplies. The AP1680 provides accurate constant voltage, constant current (CV/CC) regulation while removing the opto-coupler and secondary control circuitry. It also eliminates the need of loop compensation circuitry while maintaining stability. The AP1680 achieves excellent regulation and high average efficiency, yet meets the requirement for no-load consumption less than 30mW.