On-Board Luxeon Rebel Leds - NEC 78K0 User Manual

78K0 - Shine It!
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.
Where R = current sensor's resistor value and I
S
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:
Where V = supply voltage, V
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
•
To LED light engines

2.3 On-board LUXEON Rebel LEDs

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 with
jumper wires inserted into the four Tyco six-position receptacle connectors (refer to J1, J2, J3 and J4 in
the schematics).
=
R
S
N
MAX
= LED forward voltage current, and N
F
high-power LEDs
LUXEON Rebel
User's Manual U19610EE3V0UM00
. 0 115
I
LED
Fomula 1
= LED current. When driving the LEDs at 350 mA, the
LED
V
≤
IN
V
F
Fomula 2
MAX
= maximum number of LEDs in
14