PFC Switching Regulator Seeks LED Lighting Apps

The LC5540LD/LF is a single-stage power-factor corrected (PFC) off-line switching regulator developed to simplify system designs. This new series targets consumer and industrial markets for indoor and outdoor LED lighting applications. The series of drivers are quasi-resonant topology switching power supply ICs designed for input capacitor-less applications making it possible for systems to comply with the IEC6000-3-2 Class C standard. They incorporate separate controller and power MOSFET chips. The controller adapts the average current control method for realizing high PFCs, and the quasi-resonant topology contributes to high efficiency and low EMI noise. Protection features helps to realize low component counts and high performance-to-cost power supplies. Intended for isolated designs, these devices incorporate MOSFETs with a minimum V_DSS rating from 650 V (LC5546LD, LC5546LF and LC5547LF) to 800 V (LC5548LD and LC5549LF).  The maximum R_DS(on) is 1.1 Ω (LCD5546LD and LC5546LF), and 3.9 Ω (LC5545LD). They are capable of delivering a maximum output power of 20 to 80 W from a from a 230V AC supply, to 16 W (LC5546LD) to 55 W (LC5547LF) from a universal power supply based on the thermal rating. Note that the maximum output power can be up to 120% to 140% of this value. However, it may be limited in applications with low output voltage or short duty cycle. This series is available in DIP8 and TO220 packages that have been designed to protect the IC and overall system from excessive heat. Pricing is $1.65 each/1,000 for the LC5545LD, $1.76 for the LC5546LD, $1.94 for the LC5548LD, $2.24 for the LC5546LF, $2.46 for the LC5547LF and $2.64 for the LC5549LF.

ALLEGRO MICROSYSTEMS INC.