LLC Current-Resonant Controller IC with Built-in Full Protection Functions

The SSC3S931 from Sanken is a controller with soft-switched multi-resonant zero current control method (SMZ) for LLC current resonant switching power supplies, incorporating a floating drive circuit for a high-side power MOSFET. The product includes useful functions such as the automatic dead time adjustment and the capacitive mode detection.

The controller IC achieves high efficiency, low noise, and high cost-effective power supply systems with few external components. SMZ achieves soft switching operation during all switching periods.

This highly-integrated controller has an automatic adjustment of dead time and resonance loss detection function. This product will greatly simplify the system design and make configuring easier with cost-efficient, smaller, more efficient, and low noise power supply systems.

In addition, by setting the standby power supply to external, this product will expend less standby power than before.

Anticipated applications include switching power supplies for electronic devices such as: Audio Visual (AV) Equipment, Office Automation (OA) Equipment, Industrial Apparatus, and Communication Equipment.

Typical application (click on schematic to enlarge)

Features include:

• Soft Start Function
• Capacitive Mode Detection Function
• Reset Detection Function
• Automatic Dead Time Adjustment Function
• Protection funcitons:
  • High-side Driver UVLO: Auto-restart
  • VCC Pin Output Overvoltage Protection (VCC_OVP): Latched Shutdown
  • Input Overvoltage Protection (HVP): Latched Shutdown
  • Input Undervoltage Protection (UVP): Auto-restart
  • Overcurrent Protection (OCP): Auto-restart, peak drain current detection, 2-step detection
  • Overload Protection (OLP): Latched Shutdown
  • Optocoupler Open Protection (OOP): Latched Shutdown
  • Thermal Shutdown (TSD) : Latched Shutdown