FAN7688: Advanced Secondary Side LLC Resonant Converter Controller with Synchronous Rectifier Control

Description: The FAN7688 is an advanced Pulse Frequency Modulat...
  • The FAN7688 is an advanced Pulse Frequency Modulated (PFM) controller for LLC resonant converters with Synchronous Rectification (SR) that offers best in class efficiency for isolated DC/DC converters. It employs a current mode control technique based on a charge control, where the triangular waveform from the oscillator is combined with the integrated switch current information to determine the switching frequency. This provides a better control-to-output transfer function of the power stage simplifying the feedback loop design while allowing true input power limit capability. Closed-loop soft-start prevents saturation of the error amplifier and allows monotonic rising of the output voltage regardless of load condition. A dual edge tracking adaptive dead time control minimizes the body diode conduction time thus maximizing efficiency.
  • Features
  • Secondary Side PFM Controller for LLC Resonant Converter with Synchronous Rectifier Control
  • Charge Current Control for Better Transient Response and Easy Feedback Loop Design
  • Adaptive Synchronous Rectification Control with Dual Edge Tracking
  • Closed Loop Soft-Start for Monotonic Rising Output
  • Wide Operating Frequency (39 kHz ~ 690 kHz)
  • Green Functions to Improve Light-Load Efficiency - Symmetric PWM Control at Light-Load to Limit the Switching Frequency while Reducing Switching Losses - Disabling SR at Light-Load Condition
  • Protection Functions with Auto-Restart - Over-Current Protection (OCP) - Output Short Protection (OSP) - NON Zero-Voltage Switching Prevention (NZS) by Compensation Cutback (Frequency Shift) - Power Limit by Compensation Cutback (Frequency Shift) - Overload Protection (OLP) with Programmable Shutdown Delay Time - Over-Temperature Protection (OTP)
  • Programmable Dead Times for Primary Side Switches and Secondary Side Synchronous Rectifiers
  • VDD Under-Voltage Lockout (UVLO)
  • Wide Operating Temperature Range -40°C to +125°C
  • Applications
  • Desktop PC
  • Fully Configured Entry Level PC Server
  • Game Console
  • LED TV
  • PC Server
  • PDP TV
  • LCD TV
  • Technical Documentation & Design Resources
    Evaluation/Development Tool Information
    Availability and Samples
    FAN7688SJX
  • Status: Active
  • Compliance: Pb-free Halide free 
  • Description: Advanced Secondary Side LLC Resonant Converter Controller with Synchronous Rectifier Control
  • Package Type: SOP-16
  • Package Case Outline: 565BF
  • MSL: 1
  • Container Type: REEL
  • Container Qty: 2000
  • Inventory

  • Market Leadtime (weeks):2 to 4
  • Arrow:0
  • Newark:>1K
  • ON Semiconductor:722,000
  • Specifications
  • Topology: Half-Bridge 
  • Control Mode: Current Mode 
  • fsw Typ (kHz): Up to 690 
  • Stand-by Mode: Yes 
  • UVLO (V): 8.5 
  • Short Circuit Protection: Yes 
  • Latch: No 
  • Soft Start: Yes 
  • VCC Max (V): 20 
  • Drive Cap. (mA): 100 / 100 
  • Package Type: SOP-16 
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