Highly integrated, flexible LED driver targets automotive applications
Suitable for exterior lighting applications such as daytime running lights, headlights, taillights, stoplights, turn signals and interior lighting, The ALED6000 can drive an LED string up to 3A and offers an output voltage range of 4.5V to 61V.
The ALED6000 implements a digital dimming function and has a special pin for applying the PWM control signal. The output current is monitored with a sense resistor, where a typical voltage drop of 250 mV occurs. The quiescent current consumption is extremely low, amounting to only 2.4 mA in operation and as little as 11 µA in shutdown status. With its VBIAS pin serving as an auxiliary input and the switch to pulse-skipping operation at low load, the ALED6000 guarantees high efficiency over the entire load range.
The converter integrated on the chip is suitable for buck, buck/boost and floating boost topologies and thus brings the necessary flexibility to supply LED strings whose voltage is lower or higher than the input voltage. Voltage fluctuations can also be compensated. The converter can also operate in low dropout mode with a duty cycle of almost 100 % when the input voltage drops to near or even below the programmed output voltage.
If overcurrent occurs, the ALED6000 limits the output current to the preset maximum value. Available is a programmable soft-start circuit to limit the inrush current as well as a self-resetting overheating protection. External components can be used to set both the output current limit and the switching frequency of the converter, allowing the choke to be optimised for high energy efficiency, fast dynamic response, small size and low output ripple in conjunction with a low-ESR capacitor.
The AEC-Q100 qualified automotive LED driver ALED6000 is already in production. It is available in an HTSSOP16 package at prices starting at $2.25 (from 1,000 units). The STEVAL-ILL089V1 evaluation kit is available to help designers get started with their own projects.
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