Taillight design that just about halves system price

Currently, practically all automotive lighting options have been developed utilizing LEDs, providing elevated brightness whereas consuming much less energy. LEDs supply quite a few advantages in comparison with standard fluorescent bulbs. For the automotive taillight, all automobiles should have the next gentle features:

• TAIL(RED)
• STOP(RED)
• TURN (RED or Yellow)
• BACKUP (white)

Wow the engineering world together with your distinctive design: Design Concepts Submission Information

With out compromising on the regulatory necessities of the taillight in some functions, we will mix a number of of those features collectively as a way to scale back the general system price.

For instance, the TAIL gentle might be mixed with the STOP gentle supplied that the brightness distinction between these two features are evident at any time when activated such that:

• When the TAIL operate is activated, the LEDs shall be pushed with a decrease brightness.
• When the STOP operate is activated, the LEDs shall be of upper brightness to distinguish the TAIL operate.
• When each features are activated, STOP may have precedence over TAIL.

The restrictions for combining each the TAIL and STOP LED features are as follows:

• Every operate requires a unique brightness.
• There isn’t a communication bus from the BCM to the rear gentle module to convey operate info.

We will overcome the constraints above utilizing a easy sense circuit that allows utilizing single group of LEDs for each the TAIL and STOP operate in addition to a single LED driver with variable LED present for adjusting the brightness as proven in Determine 1. It will scale back the system price by virtually 50%.

Determine 1 A easy sense circuit and an LED driver to manage solely a single group of LEDs for each the TAIL and STOP features of an ordinary automotive taillight.

On this pattern software circuit:

• VBAT min: 9 V
• VBAT max: 1 6V

The LEDs used are the OSRAM KR DMLN31.23 Pink LEDs. A complete of 10 LEDs are utilized in a single string the place:

• Complete VF min: 2.0*10 = 20 V
• Complete VF max: 2.6*10 = 26 V

The LED driver employed is the MAX20090ATP used as a Enhance controller for driving the LEDs the place:

• LED TAIL operate present: 100 mA
• LED STOP operate present: 200 mA

Word each TAIL and STOP shall be pushed by the BCM/E-Fuse module from car. Determine 2 is a picture of the prototype driving and LED board with voltage probes measuring TAIL PWR, STOP PWR, and LED PWR. 

Determine 2 Check circuit driving and LED board with probes measuring TAIL PWR, STOP PWR, and LED CURRENT. 

Within the circuit each TAIL PWR and STOP PWR are mixed utilizing reverse safety diodes. By default, when TAIL PWR alone is utilized, the LED driver shall be configured to drive 100mA of string present. When STOP PWR is being utilized, transistor Q2 shall be activated and Q1 shall be disabled, this can change the voltage on the ICTRL pin of MAX20090 which in flip, modifications the LED string present to 180mA (Determine 3).

Determine 3 Voltage and present graph the place the LED features (TAIL or STOP) mechanically change the LED string present utilizing FETs Q1 and Q2. This in flip allows the characteristic of utilizing a single LED driver for each the TAIL and STOP features as a substitute of particular person drivers, saving ~50% design price.

The above circuit proves that, through the use of the MAX20090 together with transistor switching circuits (Q1, Q2, R9, and R10) we will use a single LED driver for driving each TAIL and STOP features.

Rajesh Subramanyam (Senior Member, IEEE) obtained his bachelor’s diploma in electrical and electronics engineering from Anna College, Chennai, India. He presently works as a senior {hardware} design engineer at an EV firm in California, USA with a core experience in automotive infotainment controller {hardware} design. Rajesh can be a member of the editorial evaluation board for the SAE worldwide journal.

Selvakumar Sonai (Senior Member, IEEE) obtained his grasp’s diploma in microelectronics from BITS Pilani, India. He presently works as a senior {hardware} design engineer at an EV firm in California, USA with a core experience in automotive infotainment controller {hardware} design. Sonai is a member of IEEE Transactions on Circuits and Techniques in addition to the editorial evaluation board for the SAE inside journal.

Logesh Sekar (Senior Member, IEEE) obtained his bachelor’s diploma in electrical and electronics engineering from Anna College, Chennai, India He presently works as a senior {hardware} design engineer at an EV firm in California, USA with a core experience in automotive infotainment controller {hardware} design. Sekar can be a member of the editorial evaluation board for the SAE worldwide journal.

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