Diodes, Inc. carries primary side regulation switchers such as the AP3968, which consists of a primary side regulation controller and a high voltage transistor, is specially designed for off-line power supplies within 12W output power. Typical applications include adapter for ADSL and auxiliary supplies. The AP3968 operates at pulse frequency modulation (PFM), and provides accurate constant voltage, constant current (CV/CC) regulation without requiring an opto-coupler and secondary control circuitry. It has internal cable compensation function for tight constant voltage regulation. The AP3968 solution has fewer component numbers, smaller size, and lower total cost.