RGB LED driver offers BSM addressing for LIN bus

October 04, 2012 // By Christoph Hammerschmidt
Chipmaker Elmos AG has developed an integrated LED driver for RGB-based illumination applications. The E521.30 is equipped with an integrated LIN transceiver with Bus Shunt Method (BSM) auto addressing. With these features, the device is ideal for interior illumination applications in vehicles.

BSM is a proven method of addressing devices connected via LIN bus. It is used by major automotive OEMs, in particular for flap control mechanisms in air conditioning units. Now Elmos takes this addressing method to RGB lighting systems in automotive interior applications. RGB LEDs are used for mood lighting in the first place; it allows the driver to adjust the light colour according to the respective situation.

The method is characterized by high fault resilience. For instance it tolerates "loss of ground" faults. It is also possible to integrate BSM-illiterate devices into the bus. Each device connected to the bus can be reached at any time. Broadcast messages are supported as well. Through a simple software routine in the slave, the bus master can validate the plausibility of the address allocation. This unique feature facilitates even to apply diagnosis functions to the address allocation.

Systems currently in the field are configured with more than 16 bus participants. In order to further expand the address scheme, the E5321.30 design has taken into account significant aspects such as an optimized slave termination and low transceiver capacitance.

The E5321.30 comes with an integrated voltage regulator which provides an output of 5V/100mA. Three LED drivers with a switching capacity of 50mA are integrated. As an option, a version with four channels is also available. The E5321.30 also offers a flash mode as well as protection against shortcut and over temperature. It meets the LIN 2.1 and the SAE-J6202 automotive standards.

For more information visit www.elmos.de