The AP1686 is a high performance AC/DC power supply controller for LED lighting application. The device uses Pulse Frequency Modulation (PFM) method to build discontinuous conduction mode (DCM) flyback power supplies. The AP1686 provides accurate constant voltage, constant current (CV/CC) regulation without requiring an opto-coupler and the secondary control circuitry. It also eliminates the need of loop compensation circuitry while maintaining good stability. The AP1686 can achieve excellent regulation and high average efficiency, yet meets no-load consumption less than 30mW. It also has an adjustable built-in line compensation function to achieve tight CC.