Diodes Incorporated AP3128 PWM Controller

Diodes Incorporated AP3128 PWM Controller is a peak-current control and multi-mode (QR+CCM) PWM controller. This controller is optimized for high performance, low standby power, and cost-effective offline flyback converters. The AP3128 controller is designed to enter burst mode at no-load/light-load and minimizes standby power consumption. This controller features a 105kHz maximum switching frequency that clamps the QR frequency to reduce switching power loss and the minimum frequency avoids audible noise. The AP3128 controller offers multi-mode control, soft start during the startup process, frequency foldback for high average efficiency, and secondary winding short protection with FOCP. Typical applications include a cell phone charger, Power Delivery (PD) application, ATX/BTX auxiliary power, Set-Top Box (STB) power supply, and open frame switching power supply.


  • Multi-mode control
  • Quasi-Resonant (QR) operation at high line voltage
  • Continuous Current Mode (CCM) operation at low line voltage
  • Non-audible noise quasi-resonant control
  • Soft start during the startup process
  • Frequency fold back for high average efficiency
  • Constant Over Current Protection (OCP)
  • Secondary winding short protection with FOCP
  • Frequency dithering for reducing EMI
  • Useful Pin fault protection:
    • SENSE pin floating
    • FB/optocoupler open/short
  • Comprehensive system protection feature:
    • VCC Overvoltage Protection (VOVP)
    • Overload Protection (OLP)
  • Brown Out Protection (BNO)


  • 10V to 50V supply voltage range
  • -40°C to 150°C operating junction temperature range
  • 80kHz (CCM mode) oscillation frequency
  • 1µA startup current
  • -800mA to 300mA output current range
  • 550mW Power Dissipation (PD) at TA < 25°C


  • Cell phone charger
  • Power Delivery (PD) application
  • ATX/BTX auxiliary power
  • Set-Top Box (STB) power supply
  • Open frame switching power supply

Block Diagram

Block Diagram - Diodes Incorporated AP3128 PWM Controller

Typical Application Circuit

Application Circuit Diagram - Diodes Incorporated AP3128 PWM Controller
發佈日期: 2021-11-08 | 更新日期: 2022-03-11