PhlatLight
®
DK-409N Series Development Kit Manual
960018 Rev A © 2008 Luminus Devices, Inc. All rights reserved.
Page 5
4. Operating Instructions
There are multiple different ways the PhlatLight DK-409N Development Kit can be operated. The LEDs
can be driven in continuous, current controlled mode via on-board POT; PWM controlled via onboard POT
or external signal, or through an external analog voltage and dipswitch for machine vision applications.
Additionally, each channel has inputs for an external function generator signal to pulse the LEDs and is
capable of pulsing at frequencies of 25kHz.
To measure the current going to the LED, use a volt meter and measure the voltage across the sense
resistor on the driver board, which is located at the “R12” position. The pads marked Sense+ and
Sense- can also be used for easier access. (See Figure 3 for details) The current can then be
calculated by the following formula:
Sense
Sense
LED
R
V
I
=
Equation 1
where V
Sense
is the voltage measured across the sense resistor in Volts (V) and R
Sense
is the value of the
sense resistor in Ohms. The sense resistor value is 0.027
Ω.
The output value will the be current going to
the LED in amps
Figure 3: Driver Locations for R12 and R15
R15
R12