Datasheet

Connecting the ACULED
The electrical circuit of a specific ACULED VHL can be found in the specific datasheet. Figure 1
shows the layout with the chip pads called Cn and the eight electrical connections labelled
Pin n. The assignment from the chip pads to the pins can be found in the ACULED datasheet for
the ACULED VHL and in table 1 for the ACULED DYO. Figure 4 is showing an example that
represents most of the visible ACULED VHLs. Please note that your specific ACULED VHL or
DYO product can be different from this example, please refer to the datasheet. It is a big benefit
of the ACULED VHL design that each LED chip can be driven individually, even if a chip type is
used twice or more. This gives you the opportunity to drive the ACULED according to your
needs, for example with one of the different four channel drivers provided by Excelitas.
Please refer to the chapter later in this application note and to the driver datasheets for more
information. If you want to connect the four chips serially, for example with a monochromatic
ACULED VHL, you only have to connect neighboured pins as shown in figure 5. To learn more
about mounting and soldering of the ACULED please refer to the application note “Mounting of
the ACULED”.
Please note that the ACULED is a highly sophisticated semiconductor product which is sensitive
to electro-static discharge (ESD) and other current and stress peaks, though most of the
ACULED VHLs have ESD protection diodes. Therefore when connecting the ACULED to a
driver and PSU make sure to use a suitable device that does not show any start-up peaks which can
damage the LED dies. Though a chip may not be damaged directly, even a very short current
peak exceeding the maximum surge current I
FM
per chip can pre-damage the LED in a way that will
dramatically decrease its lifetime.
Pin
1
2
Chip Polarity
position non IR chips
cathode (-)
C4
anode (+)
Polarity Polarity Table 1
Typical assignment of chip
IR chips PD chips
positions to pins for the
anode (+) anode (+) ACULED.
cathode (-) cathode (-)
3 cathode (-) anode (+) anode (+)
C3
4 anode (+) cathode (-) cathode (-)
5 cathode (-) anode (+) anode (+)
C2
6 anode (+) cathode (-) cathode (-)
7 cathode (-) anode (+) anode (+)
C1
8 anode (+) cathode (-) cathode (-)
Figure 4
Electrical circuit of the
ACULED VHL and DYO. It
shows the standard
assignment of the pins to the
chip pads Cn for most of the
VHL products like the RGYB.
Serial vs. parallel connection
In figure 6, left side we can see the circuit of a parallel connection of the ACULED which is
highly discouraged. LED chips should always be connected serially. The reason is the different
www.excelitas.com Driving the ACULED® VHL™ 6