08 nov 2018

Brightness reduction

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Brightness-reduction

The second instalment of our technical news serial is focussed on one question which is becoming common in installation where our products are used but where customers need less brightness than luminaires generate normally.

In this case we have, taking into account products indicated to work with constant current drivers, two options:

  1. Use of a dimmable driver regulating the brightness with a compatible dimmer.
  2. Use of a driver with lower current than standard current of the product but with an output voltage range in Direct Current (DC) in which the voltage of the luminaire is included.

Option 1 would be the most recommendable so it allows a better integration of the product in the area where installed and, besides, it provides the possibility of variate the brightness when necessary. However, and once said this, in following paragraphs we are going to talk about the second option as this is the one demanded from customers and it is the most unknown as well. In future documents we will write about issues related to brightness regulation by using different kind of dimmable drivers and their accessories to be controlled.

We must take into account we have two different items in luminaires; on the one hand we have a driver or converter, which converts the supply from altered current (AC) to DC, and, on the other hand, we have the light source, which works in DC and is fed by the driver.

Therefore, when a luminaire is designed the specifications related to current and voltage, in DC, of the light source integrated must be taken into account because the coupled driver must be able to meet them.

For example, if we have a light source running with 700mA and 36V, then we need to feed it with a constant current driver not only supplying 700mA (continuously) but also with a voltage range in which 36V is included (it could be 27-42V, for example).

In the previous example the luminaire would be working in optimal conditions. But there is a chance, when possible, of modifying the way to supply the current from the driver (with lower values), in order to reduce the power consumed and supplied by the luminaire, permanently and without any possibility of changing it by using any dimmer.

For example, using the same light source as before (700mA and 36V), we could couple it with a constant current driver which supplies 350mA and with a voltage range in which 36V is included (it could be 27-42V, for example). Therefore, thanks to the driver with 350mA we get half power, consumed and supplied, to be used in installations which require this effect. 

Obviously, the information indicated above could not be possible in all cases so it is mandatory to use drivers which are able to meet with the features of the light source, regarding to voltage and the current they supply. Normally, the luminaires in which the light source works with 300/350mA do not have the chance to reduce their brightness by this way and, as a result, they need to be regulated by using a dimmable driver.

If you need a product with the features we have described do not hesitate to contact us and we will help you to study and define the best method to get it.

Technical Department

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