FAQ: aLED Modules

Q:You have the driving current 700mA written in the datasheet of your LED module.  Can I use smaller driving current?

A:Yes, you can use smaller current. The current value 700mA mentioned in the module’s data sheet is so-called nominal/typical value that corresponds to the value Citizen announces for voltage and luminous flux (lumens) of the diode used in that LED module.

The minimum current is defined by the diode datasheet and in our 700mA modules the minimum current is 70mA. But you can also use the larger current. The maximum current is 1190mA. Please notice that you have to take care of cooling of the module in case that you use the maximum current. The warmer the module, the lower the lumen output and the shorter the lifetime.

Q: What is the IP classification of your aLED modules?

A: It is basically IP00, because if our LED arrays are not placed inside the luminaire, they are subject to dust and moisture. So if you need IP classification for your luminaire, please ensure that the luminaire casing has the desired IP classification.

Q: Ok, your aLED modules are classified as IP00, can they then be potted or protected from dust or moisture with some special coating?

A: Basically if you want to cover them with some coating or even pot them, you have to always contact the supplier of that coating or potting material to find out how it affects the LED components. Usually LED manufacturer gives some warranty for their products but this warranty applies only under certain pre-specified constraints or conditions.

Additionally, using coating may alter, and probably does so, optics of the LED components from the characteristics announced in the datasheet of the LED component manufacturer.

So basically you can use potting or special coating, but you should always check how the process affects the module.

Q: How the driving current affects the lifetime of LED module?

A: The lifetime estimations curves, lifetime hours versus temperature T_C, are informed for the LED modules at their maximum rated current. That means that maximum condition is used and then lifetime hours are announced at different T_C temperatures. The T_C point is found in every LED module and is usually located near the soldering terminal, anode or cathode, of the LED diode located near the center of the module.

Higher current means higher T_c point temperature and therefore it means shorter lifetime. On the other hand, lower driving current means lower T_c point temperature and therefore longer lifetime.

Q: Are your modules MacAdam 3-step compliant?

A: Our aLED modules follow color consistency in MacAdam 3-step. This means that from production batch to production batch color coordinate values stay within the MacAdam 3-step ellipse. This means that our modules are MacAdam 3-step compliant.

Depending on the CCT, variation in Kelvins is different for MacAdam 3-step, being ±65K for 2700K and ±140K for 4000K.

For 5000K and 6500K our LED modules are only within ANSI binning, not within MacAdam 3-step.

Q: How many aLED modules  you can drive with one 50W/90W 700mA driver?

A: It depends on the module, of course. For the sake of an example lets look at CALC0814-M17W1.

First of all, as you can see from the module’s datasheet, the power is 700mAx24.16V = 16.9W. This is power when the module is driven with 700mA typical current. If you use one 90W driver, you can drive 5 module in series connection.

Let’s do still check calculation. As given by the module’s datasheet, the maximum voltage of the module is 26.4V if all LED diodes are at maximum value of voltage binning range. This is unlikely, but should be checked anyway. Total voltage of 5 modules in series is 5×26.4V = 132V. In our example case the LED driver’s maximum output voltage is 129V. However, the case that all 40 diodes in series connection would have 3.3V (maximum voltage of voltage binning range) is very unlikely. With typical rated value of 3.02V given in the diode’s datasheet, total voltage of 5 modules in series is 40×3.02V = 120.8V, which is within driver’s output voltage range.

So 4 modules is definitely ok. Probably you could drive five, but then we would need to check that they all are from the typical binning.

If you use 50W driver, you can safely drive only 2 arrays in series connection. In our example case the LED driver’s maximum output voltage is 72V. If you drive 3 arrays in series, even the typical voltage is 3×24.16V = 72.48V, which is too much for the driver.

Q: How do you calculate aLED module’s total voltage and total current.

A: We use the information of the diode and the information how many diodes there are in series and how many in parallel.

Let’s take CALC0814-M17W1 as an example. Numbers ‘08’ and ‘14’ refer to electrical configuration of the diodes in the module. First number, ‘08’, refers to how many LED diodes are in series between the + and – terminal of the array.  Second number, ‘14’, refers to how many LED diodes are parallel in one LED chain. In this example, there are 8 pcs of LED chains in series and 14 LED diodes connected in parallel in each LED chain.

Typical value for the diode is 50mA and therefore there is 700mA going through each chain (14x50mA). That gives the total current of the module. With this typical current of 50mA, the diode forward voltage is 3.02mA and there are 8 LED chain in series in this module. This means the typical total voltage of the module is 24.16V (8×3.02V).

Q: aLED modules have quick connectors. Can I use soldered wires instead of quick connectors?

A: Yes, you can. If there are no separate solder pads for soldering wires, you can use quick connector solder pads but in this case the connector is not assembled in the assembly process. In some aLED modules both options are possible simultaneously.

Please note, that with different connectors, the delivery time might be little longer.

If you have some other questions, that were not found in this list, please feel free to ask me. I will answer to you directly and add the general questions to this FAQ later.

Tero Nurmi
Product Manager
aLED Modules
tero.nurmi@light.fi