45W Rapid Charge™ AC/DC Digital Controller

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Supports USB Power Delivery, Qualcomm® Quick Charge 4+, and Direct Charge Adapters; Companion to the iW657P USB PD 3.0 Controller

The iW1781 is a 45W output, high performance AC/DC RapidCharge™ power supply controller that supports USB Power Delivery 3.0 (USB PD 3.0) and other rapid charging protocols. 

It is optimized to work with Dialog’s iW657P USB PD interface controller in mobile device adapters to achieve fast and smooth voltage transition on request from the mobile device. The iW657P accepts fast charging protocols, including USB PD 3.0 and transmits all necessary information via an optocoupler to the iW1781, including voltage requests, output current limits, output voltage undershoot, output over-voltage, and fault and reset signals.

A full array of protection features includes Dialog’s SmartDefender™ advanced hiccup technology to address soft short circuits in charger cables and connectors, helping to prevent excessive heat build-up and damage. Learn more about SmartDefender™ smart hiccup technology here.

See the iW1791 for reduced BOM cost USB PD 3.0 designs up to 27W.

Qualcomm® Quick Charge™ is a product of Qualcomm Technologies, Inc.


  • Output power up to 45W
  • Optimized to Work with iW657P to support multiple RapidCharge™ protocols:
    • Qualcomm® Quick Charge 4+
    • Direct Charge
  • Proprietary Secondary-To-Primary Digital Communication and Built-In Decoder: 
  • Reduces BOM and Significantly Simplifies Design
  • Single Optocoupler for All Rapid Charging Information
  • Low No-Load Power Consumption <20mW


  • High Efficiency up to 90%
  • Robust Protection Features
    • Output Over-Voltage Protection
    • Over-Current Protection
  • SmartDefender™ Smart Hiccup Technology 
  • Helps Protect Cables and Connectors from Excessive Heat and Damage by Reducing Average Power During Short Circuit by at Least 50%



  • USB PD 3.0, Qualcomm® Quick Charge 4+, Direct Charge, Other RapidCharge Protocols
  • USB PD 3.0 AC/DC Power Adapters for Smartphones, Tablets, Laptops and Other Mobile Devices 
  • USB PD 3.0 Power Supplies for Set Top Boxes, Displays, Speakers
  • USB PD 3.0 in-the-wall receptacles
  • Lamps and lighting fixtures with USB PD 3.0 ports

Block Diagrams

iW1781 Functional Block Diagram
iW1781 Typical Application Circuit


Product Briefs and Summaries
Date Version
iW1781 Product Summary 06/05/2020 Rev. 0.3

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