PrimAccurate™ Off-Line Digital PWM Controller in a SOT-23 Package

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< 20mW standby power

The iW1677 is a high performance AC/DC controller designed to drive a low-cost BJT power switch in peak current mode PWM flyback power supplies up to 5W. Ideal for power adapters for smartphones, the iW1677 integrates Dialog’s PrimAccurate™ digital primary-side control, eliminating the need for the secondary-side optocoupler, 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 Dialog's 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 Supplies1
  • 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 1.7uA 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 Opto-Coupler 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 Over-Voltage and Over-Current
    • Input Undervoltage Protection
    • Sense-Resistor Short Circuit Protection


  • Power Adapters for Portable Electronics
  • Consumer Electronics Power Supplies
  • Linear AC/DC Power Supply Replacement

Block Diagrams

Typical applications diagram
Functional block dirgram



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