xiJ - Technical Manual Version 0.06
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3.8.4.4.4.
Output Wiring Example: LED Driving
LED can be driven directly by camera digital output. A series resistor must be used to limit LED current.
figure 3-19, LED Driving
LED series resistor can be calculated by the following equation:
psu
output
led
led
V
V
V
R
I
−
−
=
Where:
psu
V
power supply voltage (5V to 24V)
output
V
voltage across digital output pins (see
. 3.8.4.1 Optically isolated Digital Output
led
V
LED forward voltage (see table below)
led
I
LED current
Note:
•
Remember to use the appropriate resistor power rating
𝑃(𝑅𝐸𝑆) = 𝐼
𝑙𝑒𝑑
2
× 𝑅 = (𝑉
𝑝𝑠𝑢
− 𝑉
𝑙𝑒𝑑
) × 𝐼
𝑙𝑒𝑑
Typical LED forward voltage
LED Colour
V
led
(typ.)
V
led
(max.)
Note
Standard Red
1.7V
2.1V
Super Bright Red
1.85V
2.5V
Low power Red
1.7V
2.0V
Orange
2.0V
2.1V
Yellow
2.1V
2.2V
Green
1.9V
2.5V
Emerald Green
2.1V
2.7V
Blue
2.5V
3.7V
White
2.8V
3.8V
Infra-Red
1.3V
1.8V
Opto coupler
table 3-17, digital output, LED driving
GND (Common IO Ground)
DIGITAL OUTPUT
Camera
Power Supply
R
LED
V
PSU
V
OUTPUT
