PCIM Europe 2024

June 11 – 13, 2024

Nuremberg, Germany

onsemi NCP1681 Bridgeless Totem Pole Controller

onsemi

The NCP1681 is a PFC controller IC designed to drive the bridgeless totem-pole PFC topology. The bridgeless totem-pole PFC is a power factor correction architecture that consists of a fast switching leg driven at the PWM switching frequency and a second leg that operates at the AC line frequency. This topology eliminates the diode bridge present at the input of a conventional PFC circuit, allowing significant improvement in the power stage efficiency. The controller can be configured to operate in Continuous Conduction Mode (CCM) or Multi-Mode (CrM-CCM) operation.

Features
  • Totem Pole PFC Topology Eliminates Input Diode Bridge
  • Continuous Conduction Mode (CCM) Operation At High Power Level
  • Optional Multi-mode Operation With CCM at High Power & CrM at Medium Power Level
  • Frequency Foldback in DCM With 25 kHz Minimum Frequency
  • Skip Mode in Very Light Load Condition
  • Novel Current Sense Scheme
  • Digital Voltage Loop Compensation
  • AC Line Monitoring Circuit & AC Phase Detection
  • Near Unity Power Factor in All Operating Modes
  • PFC OK Indicator

Benefits
  • Enables High Efficiency & Compact Design
  • Optimized Efficiency For High Power Design
  • Optimized Performance Across Power Levels
  • Prevents Operation in Audible Range
  • Complies with Energy Efficiency Regulatory Standards
  • Cycle-by-Cycle Current Limit Without Hall Effect Sensor
  • Simplifies Design & Reduces External Components
  • Complies with Energy Efficiency Regulatory Standards
  • Allows Communication with Downstream Converter to Optimize System Performance

Applications
  • Power Factor Correction
  • Offline Power Supply

End Products
  • Server Power
  • Telecom 5G Power
  • Networking Power
  • Gaming Console Power Supplies
  • UHD TV Power Supplies
  • Industrial Power Supplies
Documents
➤ NCP1681 Product Overview
➤ TND6361/D Technical Article