ALED7709

概要

ALED7709x are automotive-grade (AEC-Q100 Grade1 qualified) LED drivers combining a boost/SEPIC controller and four low-side constant-current sinkers, 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. ALED7709x can work simultaneously or exclusively in standalone mode (SAM), controlled only by 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 ALED7709x supports a mixed PWM and analog dimming to improve the brightness range capability. Only the BDM provides full access to ALED7709x advanced features. PWM dimming frequency can be programmed changing the setting of the internal 16-bit counter, while an internal oscillator avoids the use of an external clock source.

The ALED7709A is dedicated to BDM while ALED7709B is more suitable for SAM. ALED7709x implement basic protections (overvoltage, overcurrent, and thermal shutdown) as well as “Open and Short” LED fault detection, with optional channel auto-disconnect in case of fault.

The devices support an optional P-channel MOSFET in series to the input. It protects the system, LED strings and channels in case of some faulty conditions, output short-to-ground or excessive input voltage transients and it also reduces the power consumption when in standby.