15
I
AVG
I
TEST
I
v TIME AVG
=
where:
I
TEST
= 3 mA for AlGaAs Red
(HLMP-X000 series)
20 mA for HER,
Yellow and Green
(HLMP-2XXX series)
Example:
For HLMP-2735 series
η
I
PEAK
= 1.18 at I
PEAK
= 48 mA
[ ]
12 mA
I
v TIME AVG
=
20 mA
= 25 mcd
[ ]
Electrical
These light bars are composed of
two, four, or eight light emitting
diodes, with the light from each
LED optically scattered to form
an evenly illuminated light
emitting surface.
The anode and cathode of each
LED is brought out by separate
pins. This universal pinout
arrangement allows the LEDs to
be connected in three possible
configurations: parallel, series, or
series parallel. The typical
forward voltage values can be
scaled from Figures 4 and 9.
These values should be used to
calculate the current limiting
resistor value and typical power
consumption. Expected maximum
V
F
values for driver circuit design
and maximum power dissipation,
may be calculated using the
following V
F
MAX models:
AlGaAs Red HLCP-X100 series
V
F
MAX = 1.8 V + I
Peak
(20
)
For: I
Peak
≤
20 mA
V
F
MAX = 2.0 V + I
Peak
(10
)
For: 20 mA
≤
I
Peak
≤
45 mA
HER (HLMP-2300/2600/2900),
Yellow (HLMP-2400/2700/2900)
and Green (HLMP-2500/2800/
2900) series
V
F
MAX = 1.6 + I
Peak
(50
)
For: 5 mA
≤
I
Peak
≤
20 mA
V
F
MAX = 1.8 + I
Peak
(40
)
For: I
Peak
≥
20 mA
The maximum power dissipation
can be calculated for any pulsed
or DC drive condition. For DC
operation, the maximum power
dissipation is the product of the
maximum forward voltage and the
maximum forward current. For
pulsed operation, the maximum
power dissipation is the product
of the maximum forward voltage
at the peak forward current times
the maximum average forward
current. Maximum allowable
power dissipation for any given
ambient temperature and thermal
resistance (R
θ
J-A
) can be deter-
mined by using Figure 2 or 7. The
solid line in Figure 2 or 7 (R
θ
J-A
of
600/538 C/W) represents a typical
thermal resistance of a device
socketed in a printed circuit
board. The dashed lines represent
achievable thermal resistances
that can be obtained through
improved thermal design. Once
the maximum allowable power
dissipation is determined, the
maximum pulsed or DC forward
current can be calculated.
Optical
Size of Light
Emitting
Area
Surface Area
Sq. Metres
Sq. Feet
8.89 mm
x
8.89 mm
67.74
x
10
–6
729.16
x
10
–6
8.89 mm
x
3.81 mm
33.87
x
10
–6
364.58
x
10
–6
8.89 mm
x
19.05 mm
135.48
x
10
–6
1458.32
x
10
–6
3.81 mm
x
19.05 mm
72.85
x
10
–6
781.25
x
10
–6
The radiation pattern for these
light bar devices is approximately
Lambertian. The luminous
sterance may be calculated using
one of the two following formulas:
I
v
(cd)
A (m
2
)
L
v
(cd/m
2
) =
π
I
v
(cd)
A (ft
2
)
L
v
(footlamberts) =
Refresh rates of 1 kHz or faster
provide the most efficient
operation resulting in the maxi-
mum possible time average
luminous intensity.
The time average luminous
intensity may be calculated using
the relative efficiency character-
istic of Figure 3 or 8,
η
I
, and
adjusted for operating ambient
temperature. The time average
luminous intensity at T
A
= 25
°
C is
calculated as follows:
(
η
I
PEAK
) (I
v
Data Sheet)
(1.18) (35 mcd)