AP3128 High-Performance PWM Controller

The AP3128 from Diodes Incorporated is a peak-current control, multi-mode [quasi-resonant + continuous current mode (QR+CCM)] PWM controller optimized for high performance, low standby power, and cost-effective offline flyback converters. At no load or light load, the IC will enter burst mode to minimize standby power consumption. The minimum switching frequency is set to avoid audible noise. When the load increases, the IC will enter QR mode with frequency foldback to improve system efficiency and EMI performance. The maximum switching frequency of about 105 kHz is set to clamp the QR frequency to reduce switching power loss.

Furthermore, the frequency dithering function is built in to reduce EMI emission. Internal piecewise linear line compensation ensures constant output power limit over the entire universal line voltage range. Comprehensive protection features, such as brown-out protection (BNO), cycle-by-cycle current limit [overcurrent protection (OCP)], V_CC overvoltage protection (VOVP), secondary-side output overvoltage protection (SOVP) and undervoltage protection (SUVP), internal overtemperature protection (OTP), overload protection (OLP), and pins’ fault protection are included. The AP3128 is available in an SO-8 package.

Features

• Multiple modes of operations
  • QR mode at high line voltage, and CCM at low line voltage
  • Multi-mode improves efficiency across all load levels
• High voltage startup
  • Achieves ultra-low standby power loss (<30 mW)
• 60V process of V_CC pin for wide range output applications
  • Lowers BOM quantity and simplifies system design for USB Power Delivery (PD) applications
• Constant OCP
  • Keeps same OCP point under wide range output conditions
• AC input BNO
  • BNO protects system from damage due to ultra-low line condition