Power Integration

Demoboard DER-631

30 W Power Supply Using InnoSwitch3TM

Topology: Flyback
Input Voltage (min.): 100.00 V
Input Voltage (max.): 132.00 V
Output 1: 15.30 V / 2.000 A

Original publication on 2017-09-12, revision 1.0


This engineering report describes an output power supply intended for USB wall outlet charger. The 30 W output (selectable 5.1 V / 6 A or 9.2 V / 3.3 A or 15.3 V / 2 A) rail is designed for a high power USB charging with Type-A or Type-C ports. The output utilizes INN3268C from the InnoSwitch3-CP family of ICs. This design shows high power density and efficiency that is possible due to the high level of integration of the InnoSwitch3-CP controller providing exceptional performance. DER-631 is a low-line input flyback converter design. The key design goals were high power density, high efficiency, low no load consumption, and best in class thermal performance. This is intended for wall outlet USB chargers.


  • 30 W compact power supply for high power USB Type-A/C port charging
  • >90% average efficiency at nominal AC input
  • <30 mW no-load input power
  • All the benefits of secondary side control with the simplicity of primary side regulation
  • Insensitive to transformer variation
  • Extremely fast transient response independent of load timing
  • Synchronous rectification for higher efficiency
  • Accurate thermal protection with hysteretic shutdown
  • Input voltage monitor with accurate brown-in/brown-out and overvoltage protection
  • Meets IEC 2.0 kV common mode surge, 1.0 kV differential surge and EN55022 conducted EMI


  Order Code SPEC Product series IR 1
RDC1 max.
(V (AC))
(V (AC))
744821110 PDF WE-CMB Common Mode Power Line Choke 0.7 10 350 250 1500

Other applications and Würth Elektronik products for this IC

  • INN3268C-H202
    Topology: Flyback, Input Voltage (min.): 100.00 V, Input Voltage (max.): 132.00 V, Output 1: 9.20 V / 3.300 A
  • INN3268C-H202
    Topology: Flyback, Input Voltage (min.): 100.00 V, Input Voltage (max.): 132.00 V, Output 1: 5.10 V / 6.300 A