RENESAS IW3688-20

The iW3688 is a single-stage, high-performance AC/DC off-line power supply controller for dimmable LED luminaires. It applies advanced digital control technology to detect the dimmer type, enabling it to provide dynamic impedance to interface with the dimmer and to control the LED brightness at the same time. With advanced dimmer detection technology, the iW3688 can operate with most wall dimmers including leading-edge dimmers (R-type or R-L type), trailing-edge dimmers (R-C type), and smart dimmers. In addition, the iW3688’s cycle-by-cycle waveform analysis technology allows for fast dimmer transient response. In no-dimmer mode, the iW3688 operates the main power converter that delivers current to the LED load in quasiresonant mode to provide high power efficiency and low electro-magnetic interference (EMI). When there is no dimmer on the line, the iW3688 optimizes the power factor and minimizes the current harmonic distortion to the AC line. The commonly utilized converter topologies for iW3688 are buck-boost and flyback. The iW3688 uses patented PrimAccurate™ primary-side sensing technology to achieve excellent LED current regulation under different AC line and LED load voltages, without using a secondary-side feedback circuit and thus eliminating the need for an optocoupler. The iW3688 minimizes the external components count by simplifying the EMI filter with Dialog’s EZ-EM |B| technology, and by integrating current sink, switching, and VCC charging circuit. Additionally, the iW3688 does not require an auxiliary winding, which eliminates the need for a custom inductor. The digital control loop of the iW3688 maintains stability over all operating conditions without the need for loop compensation components.

• Isolated/non-isolated off-line 120VAC/230VAC LED driver up to 20W output power
• Wide line frequency range (from 45Hz to 66Hz)
• Meets IEC61000-3-2 current harmonic requirement
• Total harmonic distortion < 20% with PF > 0.92
• Excellent dimmer compatibility
  • Leading-edge dimmer
  • Trailing-edge dimmer
  • Digital smart dimmer
• Wide dimming range of 1% to 100%
• Intelligent digital control integrating current sink function into power switching circuit
• Advanced IC power management and voltage sensing enables the use of off-the-shelf inductor
• Resonant control to achieve high efficiency (typical > 85% without dimmer)
• Excellent AC line distortion immunity ensures quality of product under real-life circumstances
• Over-temperature LED current foldback and shutdown
• Tight LED current regulation (±5%)
• Fast start-up (< 0.5s without dimmer)
• Multiple protection features that include:
  • LED open-circuit and short-circuit protection
  • Current sensing resistor open circuit and short-circuit protection
  • AC line over-voltage protection
  • Over-current protection

• Dimmable LED retrofit lamps up to 20W
• Dimmable LED luminaires up to 20W