Advanced STM LED Driver Tackles In-Vehicle Electrical Variability
ST Microelectronics has rolled out a single-chip automotive LED driver with a built-in DC-DC converter, aiming to cut costs, offer more design flexibility, and maintain steady lighting intensity despite changes in a vehicle’s electrical conditions.
This new chip, the ALED6000, is perfect for a range of exterior lights like daytime running lights, headlights, taillights, brake lights, and turn signals, as well as for interior lighting. It drives a single string of LEDs at up to 3A and works with an input voltage between 4.5 and 61V.
It supports digital dimming and includes a specific pin for the PWM control signal, along with an enable pin and a sync pin to ensure low noise when using multiple devices. The output current is very precise, with a variance of just 3.2%, monitored by a sense resistor with a typical voltage drop of 250mV. The chip uses just 2.4mA of current in normal operation and a minimal 11µA in shutdown mode.
Additionally, the device features a Vbias auxiliary-input pin and pulse-skipping for high efficiency under all loads. The on-chip converter supports various power configurations like buck, buck-boost, and floating-boost, accommodating LED strings that need a voltage either above or below the input voltage while handling supply fluctuations. It can also operate in low-dropout mode with a nearly 100% duty cycle if the input voltage gets close to or falls below the programmed output.
To protect against over-current, it uses pulse-by-pulse protection to limit output current to a pre-set maximum. It also includes programmable soft-start circuitry to control inrush current and thermal protection with automatic recovery.
Both the output-current limit and the converter’s switching frequency can be adjusted using external components. This customization allows for optimized energy efficiency, quick dynamic response, compact size, and low output ripple with a low-ESR capacitor.
The ALED6000 is AEC-Q100 qualified and is now available in the HTSSOP-16 package. Designers can kick-start their projects with the STeval-ILL089V1 evaluation kit.
