ALED7709 Automotive-Grade LED Driver

STMicroelectronics' ALED7709 is an automotive-grade (AEC-Q100 compliant) LED driver combining a boost/SEPIC controller and four low-side constant-current sinkers. It is designed to drive strings of high-brightness LEDs. The switching converter section provides the supply rail for the LED strings, whose value is constantly optimized for maximum efficiency. The boost/SEPIC controller supports the external synchronization and spread spectrum. The ALED7709 can work simultaneously or exclusively in standalone mode (SAM), controlled only by pulse width modulated inverter (PWMI) signal, and in bus-driven mode (BDM) through an I²C serial interface.

The brightness of the four LED strings can be controlled either in global or local mode. In global mode, the ALED7709 supports mixed pulse width modulation (PWM) and analog dimming to improve the brightness range capability. Only the BDM provides full access to ALED7709A advanced features. PWM dimming frequency can be programmed by changing the setting of the internal 16-bit counter, while an internal oscillator avoids the use of an external clock source.

ALED7709A is dedicated to BDM. The ALED7709A implements basic protections (overvoltage, overcurrent, and thermal shutdown) and open and short LED fault detection with optional channel auto-disconnect in case of fault. The device supports an optional P-channel MOSFET in series to the input. This MOSFET protects the system, LED strings, and channels in case of faulty conditions, output short-to-ground, or excessive input voltage transients. It also reduces power consumption when in standby.