The iW1677 is a high-performance AC/DC controller designed to drive a low-cost bipolar junction transistor (BJT) power switch in peak current mode PWM flyback power supplies up to 5W. Ideal for power adapters for smartphones, the iW1677 integrates Renesas' PrimAccurate™ digital primary-side control, eliminating the need for the secondary-side optocoupler, and reducing component count and solution cost. The iW1677 integrates an active start-up circuit that allows for fast turn-on without impacting operating current consumption. The device easily meets the US DoE’s external power supply standard and the EU’s Code of Conduct, Version 5, Tier 2 standard, with a no-load power consumption of less than 20mW. Additional features include Renesas' proprietary EZ-EMI™ technology, quasi-resonant control for optimal efficiency at heavy loads, cable and connector voltage drop compensation options, full protection from fault conditions, and tiny packaging.