Diodes Incorporated AL8841Q Automotive Step-Down LED Drivers are hysteresis mode DC-DC step-down converters designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The devices operate from an input supply between 4.5V and 40V and provide an externally adjustable output current of up to 1A for TSOT25 and 1.5A for the MSOP-8EP package. These converters can provide up to 60W of output power depending upon the supply voltage and external components. The AL8841Q integrates a power switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current.
Applying an external control signal to the CTRL pin enables dimming. The CTRL pin will accept either a DC voltage or PWM signal. An external capacitor from the CTRL pin to the Ground can adjust the soft-start time. Applying a voltage of 0.3V or lower to the CTRL pin will shut down the power switch. The Diodes Incorporated AL8841Q is available in the thermally enhanced MSOP-8EP package and the small footprint TSOT25 package.