Quasi-Resonant Controller IC for AC-DC Power Supplies

The SSC1S310A from Sanken Electric is a quasi-resonant mode controller IC for switching power supplies. The IC incorporates a startup circuit and a standby function to reduce a power consumption and standby power. In normal operation, the quasi-resonant mode operation achieves high efficiency and low noise.

In addition, in medium to low load conditions, the operation mode is automatically changes the quasi-resonant mode to the bottom-skip mode to improve efficiency. The IC is provided in the SOIC8 package. The power supply that is a low component counts and a high performance-to cost can be achieved by the rich set of protection features.

Targeted applications include digital appliances, office automation equipment, white goods, industrial apparatus, communications facilities, and so on.

SSC1S310A block diagram

Features include:

• Multi-Mode Control
  • (High efficiency operation in all range of loads)
• Automatic Standby Function
  • (Standby power is improved by burst oscillation mode)
• Input Power at No Load:
  • <30mW at 100Vac
  • <50mW at 230Vac
• Bottom-Skip Function
  • (Switching loss in medium to low loads is reduced)
• Step-on Burst Oscillation Function
  • (Transformer audible noises are reduced)
• Bias Assist Function
• Soft-Start Function
• Adjustable Startup Voltage
• Maximum On-time Limitation Function
• VCC Operational Range Expanded
• Leading Edge Blanking (LEB) Function
  • (External Filter Components are reduced)
• Protection Functions
  • Overcurrent Protection (OCP): Pulse-by-pulse
  • Overvoltage Protection (OVP)
  • Overload Protection (OLP)
  • Thermal Shutdown (TSD)