This page goes over the details of which lights boards we have in the car and the required details for driving them and for heat dissipation calculations.
Tmax Tjmax = XX 100 degrees C Look at LED lifetimes vs operating temperature - LEDs have very high lifetime, but it seems like light output decreases when temperature rises. We will chose 100C as upper limit for Tj
Tamb = 35 degrees C Max ambient temperature (car temp on hot day in desert)LED Thermal Resistance
Check datasheet for LED thermal resistance - it depends on the color of the LED. Use the typical values
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LED Color
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LED Thermal Resistance (Typical, Degrees C / W)
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White
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9
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Amber
...
7
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Red
...
5
We want to ensure that our Boost LED Drivers are able to drive all of the LEDs that we will be using. This table will go over the required parameters to check this. Vf is the most important parameter for this, and must be significantly higher than the input voltage of the board to ensure that accurate regulation is achieved. Check datasheet of LED driver for more specifics.
Board |
|---|
Color |
|---|
Min Cd | Max Cd | Chosen CD | LED Count | Total Vf |
|---|
Worst Case Power Dissipation
Max Thermal Resistance to Ambient
Daytime Running Lights
White
6 (not finalized)
6 x 2.9 = 17.4V
17.4V x 0.35A = 6.09W
Side Turn Indicators
Amber
Rear Brake
Red
6 (not finalized)
6 x 2.2 = 13.2V
13.2 x 0.35A = 4.62W
(Current may have to be increased)
(50 - 35) / 4.62W = 3.24 C/W
Chosen Drive Current | Driver Type | Min LED | |||||||
|---|---|---|---|---|---|---|---|---|---|
DRLS | White | Boost | |||||||
Top Brake | Red | Boost | |||||||
Rear Brake | Red | Boost | |||||||
Rear Turn | Amber | ||||||||
Front Turn | Amber | ||||||||
Side Turn | Amber | Buck | |||||||
BPS Strobe | White | Buck |