Diodes Incorporated
SO 8

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The AL1666A is a high performance single stage Flyback and Buck-boost controller, targeting dimmable LED lighting application. It is a primary side regulation (PSR) controller which can provide accurate Constant Current (CC) regulation without opto-coupler and secondary control circuitry. It is operating at BCM mode which results in good EMI and efficiency, and keeps high PF and low THD under universal input voltage. The AL1666A can support analog/PWM dimming modes. When a 0 to 2.4V DC signal is applied on ADIM pin, the device will operate in analog dimming mode; when a digital signal is applied on PWMD pin and the ADIM pin is connected with hundreds of nF capacitors, the device will work at PWM-to-DC dimming mode. The dimming range is 1% to 100%. The AL1666A has rich protection features. It integrates multiple protections including Under Voltage Lock Out (UVLO), Output Over Voltage Protection (OVP), Output Short Circuit Protection (OSP), Over Current Protection (OCP), Winding Short Circuit, Secondary Diode Short, Internal Thermal Fold-Back Protection (TFP) and Over Temperature Protection (OTP). The AL1666A is available in SO-8 (Standard) package.


  • Primary Side Regulation without Opto-Coupler
  • Valley Switching for Low Switching Loss
  • Support Analog and PWM-to-DC Dimming
  • Analog/PWM-to-DC Dimming Range: 1 to 100%
  • Tight CS Reference Voltage 0.4V±5%
  • High PF > 0.9 and Low THD < 20%
  • High Efficiency
  • Internal Protections
    • Under Voltage Lock Out (UVLO)
    • Output Over Voltage Protection (OVP)
    • Output Short Protection (OSP)
    • Over Current Protection (OCP)
    • Winding Short Circuit Protection
    • Secondary Diode Short Protection
    • Internal Thermal Fold-back Protection (TFP)
    • Over Temperature Protection (OTP)
  • Tight LED Current Variation Range

        LED Current Line Regulation: ±2% (90VAC to 305VAC)

        LED Current Load Regulation: ±2% Full Load to Half Load

  • Package: SO-8 (Standard)
  • Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
  • Halogen and Antimony Free. “Green” Device (Note 3)
  • For automotive applications requiring specific change control (i.e. parts qualified to AEC-Q100/101/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative.



  • General LED Lighting Driver with Dimming Function
  • 0V to 10V Dimming Luminaires
  • General Purpose Constant Current Source
  • Smart LED Lighting

Product Specifications

Product Parameters

Minimum Input AC Voltage (VAC) 85
Maximum Input AC Voltage (VAC) 305
Maximum DC VDD (VDC) 23
LED Current (mA) External MOSFET
Frequency (kHz) 80K
Accuracy (%) 1.5 %
Efficiency (%) > 85 %
Dimming Analog, PWM to Analog
SupplyCurrent (mA) 2 mA
Temperature Range (°C) '-40 to 105 °C

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