STMicroelectronics has rolled out ALED6000 single-chip automotive LED driver with integrated DC/DC converter that is a low-BoM (Bill of Materials) solution that allows design flexibility and keeps the lighting intensity consistent with electrical conditions within the vehicle fluctuate.
Suitable for exterior lighting such as daytime running lights, headlights, rear lights, stop lights, and turn signals, as well as interior lighting, the ALED6000 drives a single string of LEDs at up to 3A and has a wide input-voltage range of 4.5V to 61V.
The ALED6000 implements digital dimming and has a dedicated pin to apply the PWM control signal. There is also an Enable pin and a Sync pin that ensures low noise in multi-device applications.
The output current is accurate within 3.2% and is monitored efficiently with a sense resistor that has a typical voltage drop of 250mV. The quiescent current is extremely low, at just 2.4mA in operation and 11µA in shutdown. Also featuring a VBIAS auxiliary-input pin and pulse-skipping operation at light load, the ALED6000 ensures high efficiency across the load range.
The on-chip converter allows buck, buck/boost, and floating-boost topologies, giving flexibility to power LED strings that require a voltage above or below the input voltage while also handling supply fluctuations.
In addition, the converter can operate in low-dropout mode with close to 100% duty cycle if the input voltage falls near or below the programmed output.
In the event of an over-current, the ALED6000 invokes pulse-by-pulse protection to limit the output current at the preset maximum. There is also programmable soft-start circuitry to limit inrush current and thermal protection with auto-recovery.
Both the output-current limit and converter switching frequency can be selected using external components, allowing the inductor to be optimized for high energy efficiency, fast dynamic response, small size, and low output ripple in conjunction with a low-ESR capacitor.