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 no-load power consumption 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.


  • Meets proposed mandatory federal efficiency standards for external power supplies
  • Intrinsically low noise solution - No audible noise over entire operating range
  • Easily meets Energy Star® AC/DC power supply efficiency specs (Rev. 2.0)
    • Less than 20mW no-load power consumption
  • Low 1.7µA start-up current
  • Active start-up circuit to reduce turn-on time
  • 72kHz PWM switching frequency
  • Voltage offset compensation for voltage loss in cables and connectors (4 options)
  • PrimAccurate™ - Primary-side control, no optocoupler needed
  • Quasi-resonant control for optimal efficiency
  • EZ-EMI™ design to easily meet global EMI specifications
  • Fast dynamic load regulation
  • Fully protected from fault conditions
    • Over-temperature protection
    • Output overvoltage and overcurrent
    • Input undervoltage protection
    • Sense-resistor short circuit protection




  • Power adapters for portable electronics
  • Consumer electronics power supplies
  • Linear AC/DC power supply replacement


Type Title Date
Datasheet PDF 1003 KB
Brochure PDF 8.73 MB
Brochure PDF 5.49 MB 日本語
Other Log in to Download ZIP 3.02 MB
White Paper PDF 597 KB
5 items

Design & Development