LC5550LD Series: Single-Stage Power Factor Corrected High Efficiency Non-Isolated Buck LED Driver

LC5550LD series are PWM and quasi-resonant topology non-isolated buck LED driver ICs. They incorporate separate controller and power MOSFET chips, and are designed for input capacitorless applications. The controller adapts the average current control method for realizing high power factors. The rich set of protection features helps to realize low component counts, and high performance-to-cost power supply.


  • LED lighting fixtures
  • LED light bulbs
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  • PWM and quasi-resonant topology
  • Integrated on-time control circuit (it realizes high power factor by average current control)
  • Integrated soft-start circuit (reduces power stress during start-up on the incorporated power MOSFET and output rectifier)
  • Integrated bias assist circuit (improves startup performance, suppresses VCC voltage droop during operation, and allows use of low-rated ceramic capacitor on VCC pin)
  • Integrated Leading Edge Blanking (LEB) circuit
  • Integrated maximum on-time limit circuit
  • Protection features:
    • Overcurrent protection (OCP): pulse-by-pulse
    • Overvoltage protection (OVP): latched shutdown
    • Overload protection (OLP): latched shutdown
    • Thermal shutdown (TSD): latched shutdown

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Typical Application

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
LC5555LD 8-lead DIP -55°C to 125°C Yes View Data New Contact your
local sales rep
Check Stock
LC5556LD 8-lead DIP -55°C to 125°C Yes View Data New Contact your
local sales rep
Check Stock

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