The ISL1904 is a high-performance, critical conduction mode (CrCM), flyback controller used for single-stage conversion of the AC mains to a constant current source with power factor correction (PFC). The controller regulates the output current by monitoring the primary side switching current so the feedback signal does not cross the isolation barrier. Operation in CrCM allows near zero-voltage quasi-resonant switching (ZVS) for improved efficiency while maximizing magnetic core utilization. The ISL1904 LED driver provides all of the features required for high-performance dimmable LED ballast designs and supports AC or DC input, isolated or non-isolated flyback and boost topologies. This advanced BiCMOS controller features all of the functions required to design low cost low parts count LED driver.


  • Excellent LED current regulation over line, load, and temperature
  • 0 - 100% dimming with leading-edge (triac) and trailing-edge dimmers
  • Power factor correction for up to 0.995 power factor and less than 20% harmonic content
  • Critical conduction mode (CrCM) operation for quasi-resonant high efficiency performance
  • Supports universal AC mains input
  • Configurable for PWM or DC current dimming control of LEDs
  • Monitors FET switching current for load regulation
  • Supports isolated and non-isolated boost and flyback topologies
  • Closed loop soft-start for no overshoot
  • OFFREF feature to set dimming off-point to improve fixture performance matching
  • -40°C to +125°C operation
  • Pb-free (RoHS compliant)


  • Industrial and commercial LED lighting
  • Retrofit LED lamps with triac dimming
  • Universal AC mains input LED retrofit lamps
  • AC or DC Input LED ballasts

Product Options

Part Number Part Status Pkg. Type Carrier Type MOQ Buy Sample
Active QSOP Tube 98
Active QSOP Reel 2500
Active QSOP Reel 250
Active QSOP Reel 1000


Title language Type Format File Size Date
Datasheets & Errata
ISL1904 Datasheet Datasheet PDF 1.01 MB
User Guides & Manuals
ISL1904DEMO1Z User Guide Manual PDF 2.50 MB
Application Notes & White Papers
AN1681: Grounding Techniques Application Note PDF 509 KB
AN1684: Nonideality of Ground Application Note PDF 397 KB
Five Easy Steps to Create a Multi-Load Power Solution White Paper PDF 846 KB

Boards & Kits

Part Number Title Type Company
ISL1904DEMO1Z Offline Triac Dimmable Isolated LED Driver Demonstration Board Demonstration Renesas