Semtronics Micro Systems

Internal MOSFET

SM2601B is a fly back LED constant current driver chips a precision double-winding primary feedback. Chip in discontinuous inductor current mode is particularly suitable for 85VAC ~ 265VAC full voltage input range of low-power isolated LED lighting systems.

SM2601B uses source-driven approach and proprietary dual-winding transformer control technology to feedback LED output current LED constant current output can be achieved without the use of an auxiliary winding of the transformer. Meanwhile SM2601B low operating current without auxiliary winding to supply power to the chip.

SM2601B work in the primary side feedback mode, the primary side feedback information which can achieve high-precision LED constant current output, does not need an opto-coupler, secondary feedback circuitry and any compensation circuitry. Additionally, SM2601B internal integration of 650V power tube, so that only a few external components, to achieve high-precision LED constant current output, significantly simplifies the design of LED lighting systems.

Key Features

  • Integrated 650V power MOSFET
  • PSR mode, no secondary feedback circuit
  • Dual transformer winding control technology
  • Low operating current without auxiliary power winding
  • Wide input voltage range
  • ± 5% LED current accuracy
  • VCC power clamp
  • LED open-circuit protection
  • LED short-circuit protection
  • Chip supply voltage protection
  • Over temperature protection
  • Auto-restart function
  • System is small, low cost BOM
  • Use SOP8L package


  • GU10 LED Spotlight
  • E17 / E27 LED candle light
  • LED Bulb
  • Other LED Lighting

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