Description

LC5540LD series is a quasi-resonant topology switching power supply IC, designed for input capacitorless applications, and making it possible for systems to comply with the harmonics standard (IEC61000-3-2 class C). It incorporates separate controller and power MOSFET chips. The controller adapts the average current control method for realizing high power factors, and the quasi-resonant topology contributes to high efficiency and low EMI noise. The rich set of protection features helps to realize low component counts, and high performance-to-cost power supply.

Features and Benefits

? Integrated on-width control circuit (it realizes high power factor by average current control)

? Integrated startup circuit (no external startup circuit necessary)

? Integrated soft-start circuit (reduces power stress during start-up on the incorporated power MOSFET and rectifier)

? Integrated bias assist circuit (improves the startup performance, suppresses VCC voltage droop during operation, allows reduction of VCC capacitor value as well as use of a ceramic capacitor)

? Integrated Leading Edge Blanking (LEB) circuit

? Integrated maximum on-time limit circuit

? Dual-chip structure, with an avalanche-guaranteed power MOSFET (allows simplified surge suppressing circuits)

? Protection features:

? Overcurrent protection (OCP): pulse-by-pulse

? Overvoltage protection (OVP): latched shutdown

? Overload protection (OLP): latched shutdown

? Thermal shutdown (TSD): latched shutdown

Applications

? LED lighting fixtures

? LED light bulbs