AS5818Phase Dimming, Primary-Side-Regulation PWM Controller with Active PFC

The AS5818 is a TRIAC phase dimmable, primary-side regulated PWM controller that achieves high power factor and flicker-free TRIAC phase dimming output LED current for an isolate lighting application in a single stage converter.

The proprietary real-current control method controls LED current accurately from primary side information. It removes the need for secondary feedback circuitry while achieving excellent line and load regulation. It also eliminates the need for loop compensation components while maintaining stability over all operating conditions.

By integrating active power factor correction and working in boundary conduction mode, it reduces the MOSFET switching losses. With ultra-low quiescent current and operating current, the AS5818 reduces total power consumption and provides a high efficiency solution for lighting applications.

The multi-protection features of the chip greatly enhance the system reliability and safety. The AS5818 provides protective functions such as over-voltage protection, short-circuit protection, over-temperature protection and VCC UVLO. Cycle-by-cycle current-limit level is automatically reduced to minimize output current and protect external components in an over-temperature condition.

The AS5818 is available in a single SOP-8L exposed pad package, and the operating temperature is from –40°C to +125°C.

• Flicker-free Phase-controlled TRIAC Dimming
• Isolated Fly-back Topology with Minimum Number of External Components
• High Power Factor Correction (>0.95)
• Accurate Constant Current Output
• Boundary Conduction Mode Operation
• Real Current Control without Secondary-feedback Circuit
• Under Voltage Lock Out
• Over Voltage Protection
• Over Current Protection
• Over Temperature Protection
• Low THD
• Superb EMI Performance
• SOP-8L Exposed Pad Package

• LED Driver
• Leading Edge / Trailing Edge Dimmable LED Lighting
• Lamp Indicators
• Candle Light
• Low Cost Solution
• Constant Current Source