DIODES AL8843SP-13 DC-DC step-down converter

Description

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.

Features

 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%  

 Soft-Start  

 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)

Applications

 LED Retrofit for Low Voltage Halogen  

 Low Voltage Industrial Lighting  

 LED Backlighting  

 Illuminated Signs  

 External Driver with Multiple Channels