Digital LED lighting control for automotive applications

November 10, 2016 // By Graham Prophet
Inova Semiconductors has unveiled a new digital LED concept for automotive applications with the first LED product to be available from Dominant Opto Technologies in 1Q2017. This will be the first product developed under ISELED, an open alliance formed to provide a full ecosystem for the new digital LED right from its very inception.

The open ISELED Alliance curently comprises Inova Semiconductors, Dominant Opto Technologies, NXP, TE Connectivity, and Pforzheim University. Its aim is to create LED-related products and solutions for the automotive market. These solutions are to be based on an entirely new in-car LED lighting concept that drives down costs, simplifies control, and expands the functionality of LED lighting and display solutions.

 

This generation of in-car lighting will typically consist of 10 to 30 LEDs mounted on a flexible strip. Each group of one red, green, and blue LED will form a 'pixel', with at 24-bit resolution/16 million colours.

 

At the present time, in order to individually control LEDs, a microcontroller containing LED-specific data is needed for each individual RGB LED. Such a solution is typically too cumbersome and expensive to be viable. Also, it is not feasible to capture individual LED life parameters such as functionality and temperature. The IseLED concept is to create a compact smart LED driver that is directly integrated with three colour LEDs into a 3 x 4 mm package.

 

The first solution consists of a driver from Inova with a bidirectional serial interface and daisy-chain capability integrated by Dominant Opto Technologies into a single compact package with three LEDs (red, green and blue). The new package will come with pre-calibration of the required white point from the factory. The driver includes three constant current mode (CCM) drivers to control the red, green and blue LEDs. For temperature and manufacturing tolerance compensation, the brightness of each individual LED can be controlled with 12-bit resolution.

 

The extremely low thermal resistance of the housing, which is 30% lower than in comparable products, reduces the power consumption of the LED by delivering better light efficiency with cooler LEDs. A built-in temperature sensor ensures accuracy, whilst the calibration values of the CCM LED drivers and temperature compensation parameters are securely stored in non-volatile memory, an indispensable prerequisite