The AL8843 is a hysteresis mode DC-DC step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device can operate from an input supply between 4.5V and 40V and provide an externally adjustable output current up to 3A. Depending upon supply voltage and external components, this converter can provide up to 60W of output power.
The AL8843 integrates the power switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current.
Dimming can be realized by applying an external control signal to the CTRL Pin. The CTRL Pin will accept either a DC voltage signal or a PWM signal.
The soft-start time can be adjusted by an external capacitor from the CTRL Pin to Ground. Applying a voltage of 0.3V or lower to the CTRL Pin will shut down the power switch.
LED Retrofit for Low Voltage Halogen
Low Voltage Industrial Lighting
External Driver with Multiple Channels
Wide Input Voltage Range: 4.5V to 40V
Output Current up to 3A
Internal 40V NDMOS Switch
Typical 4% Output Current Accuracy
Single Pin for On/Off and Brightness Control by DC Voltage or PWM Signal
Recommended Analog Dimming Range: 10% to 100%
High Efficiency (Up to 97%)
LED Short Protection
Inherent Open-Circuit LED Protection
Over Temperature Protection (OTP)
Up to 1MHz Switching Frequency
SO-8EP Packages Available in Green Molding Compound (No Br, Sb)