4. Determine value of external current limiting
The linear forward voltage models for the other
HPWT-MH00 forward voltage categories are
shown below:
resistor, R, for each forward voltage category:
For SuperFlux LED emitters from lower forward
voltage categories, the value of the external
resistor, R, will need to be increased (using
Equation #3.2) in order to maintain the same
nominal forward current.
HPWT-
MHOO
Voltage
Category 2
Voltage
Category 3
Voltage
Category 4
Voltage
Category 5
Voltage
Category 6
VO
RS
=
=
1.87 V
8.2 ohm
1.91 V
9.2 ohm
1.94 V
10.5 ohm
1.96 V
11.6 ohm
2.03 V
12.4 ohm
NOM
NOM
For VIN DES = 12.8 V, VD = 0.8 V, IF DES = 33.6 mA, x = 1, y = 4:
HPWT-
MHOO
Voltage
Category 2
Voltage
Category 3
Voltage
Category 4
Voltage
Category 5
Voltage
Category 6
R =
102 ohm
93 ohm
84 ohm
77 ohm
66 ohm
5. Determine minimum thermally stabilized
luminous flux:
Design currents for SuperFlux LED emitters at
higher luminous flux categories can be
determined using Figure 3 from the SuperFlux
LED Data Sheet. This can be done by computing
a new “relative luminous flux” equal to the
desired luminous flux divided by the minimum
luminous flux category bin limit and then reading
a new value of forward current from Figure 3.
The thermally stabilized luminous flux of the
SuperFlux LED emitters from the lowest
expected luminous flux category can be
determined using Figure 3 from the SuperFlux
LED Data Sheet.
For HPWT-MH00, luminous flux category F (3.0
lm minimum) and IF DES = 33.6 mA:
The same minimum luminous flux obtained from
a HPWT-MH00 luminous flux category F (3.0 lm)
driven at 33.6 mA can be obtained from a
HPWT-MH00 from the following luminous flux
categories when driven at the specified forward
current:
Then: F V MIN = (3.0)(0.54) = 1.62 lm, (i.e. “relative
luminous flux” = 0.54) from HPWT-MH00 Data
Sheet, Figure 3
6. Determine design currents for brighter
SuperFlux LED emitters:
25
LUMILEDS [ LUMILEDS LIGHTING COMPANY ]
