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EV-K0-HCD Evaluation Kit User's Manual
2.1
Power Supply
The EV-K0-HCD board requires a 10 to 24 V
(W) to light the high-power LEDs. The barrel-type power jack mounted on the board accepts a 2.1 mm
center pole connector (center positive).
2.2
LED Drivers
The board's four-channel LED drivers are set in buck topology for 350 milliamps (mA) of constant
output current. However, you can increase output current up to 700 mA by changing the current
sensor's resistor values using the following formula (refer to R1, R2, R3 and R4 in the schematics).
Please note that you need to change the inductors (refer to L1, L2, L3 and L4 in the schematics)
current rating accordingly if you wish to drive at more than 350mA.
R
= 0.115 / I
S
Where R
= current sensor's resistor value and I
S
the current sensor's resistor value should be set to 0.33 ohm (Ω).
The number of LEDs that can be used in series per channel is determined by the supply voltage and
the LED forward voltage using this formula:
≤ V
N
/ V
MAX
IN
Where V
= supply voltage, V
IN
in series per channel.
Generally, the sum of LED forward voltages must be less than the supply voltage for buck mode
operation. For a 24V power supply, for example, a maximum of six LEDs with 3.5V forward voltage
may be used in series per channel.
LED driver outputs can be connected in one of three configurations:
• To the on-board
• To LED boards with LUXEON K2 high-power LEDs from Future Lighting Solutions
• To LED light engines
2.3
On-board
There are four LUXEON Rebel high-power LEDs mounted on the back of the EV-K0-HCD board, one
red (R), one green (G), one blue (B) and one white (W). By default, the board is set to drive the LEDs
(Formula 1)
LED
(Formula 2)
F
= LED forward voltage current, and N
F
LUXEON Rebel
LUXEON Rebel
power supply with output wattage of at least 5 watts
DC
= LED current. When driving the LEDs at 350 mA,
LED
high-power LEDs
LEDs
4
= maximum number of LEDs
MAX
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