15W AccuSwitch™ AC/DC Digital Primary-Side Switcher Eliminates Optocoupler and Maintains Excellent Cross-Regulation Accuracy

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72kHz integrated 800V BJT optimized for 5Vout

The iW1820 AccuSwitch™ digital PWM controller integrates a highly accurate control circuit with an 800V BJT power switch to provide a complete solution for off-line power conversion at up to 15W of output power.

Dialog’s PrimAccurate™ primary-side digital control algorithms eliminate the need for failure-prone optocouplers and ensure excellent cross-regulation accuracy, to enable the longer operating lifetime, high performance and reduced cost required for white goods applications.

The output is designed to smoothly start-up into large capacitors, while maintaining a quick turn-on time.  It operates in quasi-resonant mode to optimize efficiency and incorporates a low-power mode that achieves <30mW of no-load power consumption to meet global energy efficiency regulations. 


  • 15W Output, Optimized for 5Vout
  • AccuSwitch™ integrated 800V Power BJT
  • PrimAccurate™ Primary-Side Control
  • No Optocoupler Needed
  • Intelligent Digital Control Loop for Accurate Voltage Cross-Regulation
  • Meets Global Energy Efficiency Standards
    • <30mW No-Load Power Consumption
    • Quasi-resonant Control for Optimal Efficiency
  • Adaptively Controlled Soft Start-up
  • Fast, Smooth Start-up into Large Capacitive Loads (up to 6,000µF)


  • EZ-EMI® Design
    • Reduces Filtering Requirements
    • Easily Meets Global EMI Specifications
  • Fully Protected from Fault Conditions
    • Built-In Over-Temperature Protection
    • Output Over-Voltage and Over-Current Protection
    • Sense-Resistor Short Circuit Protection
  • Thermally Efficient SO-10 Batwing Package


  • Power Adapters/Chargers for Media Tablets, Smartphones, Consumer Electronics
  • AC/DC Power Supplies for Home Appliances, Industrial Electronics

Block Diagrams

Typical application diagram
Functional block diagram


Date Version
iW1820 Datasheet 17/06/2020 Rev. 1.4

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