Monthly Archives: August 2016

How to use Citizen LED simulator

Datasheets are essential part when you compare how different light sources work in your solution. Usually it can be time taking and exhausting to glance at datasheet and find values you are looking for. This gets even harder if you have multiple LEDs or different LED packages, which would mean that you have look at multiple datasheets to get different values.

This is the reason why Citizen has created a Citizen LED simulator. The simulator is very easy to use and makes comparing different LED packages a lot easier. If you haven’t yet tried it or you don’t have the simulator, you can download it for free from our website.

Citizen LED simulator basic view

Citizen LED simulator basic view.

The steps

Follow these steps to use the simulator.

You can choose desired CCT and Ra and selection simulator shows packages and product codes of existing products.

You can choose desired CCT and Ra and selection simulator shows packages and product codes of existing products.

  1. Select the CCT and Ra

First you need to select desired CCT and Ra from condition input field.

You can choose desired CCT and Ra and the selection simulator shows packages and product codes of existing products.

  1. Choose whether you want to search based on the desired lumen amount or driving current

After you have selected color temperature and CRI value, you can choose between driving current (forward current in simulator) or desired luminous flux.

  1. Input the Tc-temperature

Then you can input Tc-temperature. If you have no idea how much Tc is or would be in your solution, values around 60 degrees are realistic to use as many light sources reach temperatures close to that while being used.

Example

In this example, I have chosen that I want my LED to be 4000K, Ra80 Min. And I want to see what options we have to get around 3000 lumens out from luminaire. Luminaire optics etc. will drain around 300-400 lumens in my solution. So I have determined that I need 3400 warm lumens from LED and estimated that Tc-temperature is 60 degrees.

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I can see that I have ten different LED packages I can get the 3400 lumens from. In first column after product code you can see what current you should use to get these values. If you don’t have LED driver, in which you can choose output current, it is recommended to then select current value you have LED drivers available in. In this case, 700mA seems to be a good choice as many of the LED’s have driving current close to that.

So I change “forward current” instead of “luminous flux” from the condition input and insert 700mA.

LED packages which give you desired lumens with 700mA. We still have six options to choose from.

LED packages which give you desired lumens with 700mA. We still have six options to choose from.

This will give me a list of LEDs I can use with 700mA driver. And more importantly give me a good overview of LED packages that can give me my desired lumen amount. If you have problem that you can’t find driver with suitable current, you can contact me for help.

In this case, CLU028-1204 would suit my lumen need quite nicely and CLU048-1212, would probably be an overkill for this application. All the other options, might suit my solution although they give roughly 10% more lumens. Whether this is ok, depends really on my application and desired efficacy.

Other applications

Citizen LED simulator is also powerful tool to use when you want to see easily how much lumens you get when driving LED with different currents. Good example is that if you have LED driver which has different current options and flexible LED package, you can use only two components to realize many different lumen packages.

As an example I did this exercise with ELT 42W multicurrent LED-driver and Citizen CLU038-1205 LED package. This driver has option to select different driving currents with dipswitch. If we take Esko’s advice and look from driver datasheet, we can see that output voltage area is suitable from 500mA to 1000 mA.

Below you can see LED characteristics with different current. I have also added forward current column to make this table easier to read. Tc temperature is 60 degrees in all cases.

Table with CLU038-1205 4000K Ra80 LED from 500mA to 1000mA.

Table with CLU038-1205 4000K Ra80 LED from 500mA to 1000mA.

You can also use the LED simulator to estimate the amount of lumens lost due to your luminaire (optics etc.). If you measure LED Tc-point and input the driving current you use to simulator, you should have pretty good estimation that how much lumens you should get out from your luminaire.

If you find out that the loss is too big, the you can either change the LED to a different package or improve the optics of your luminaire.As you can see, you can use this driver & LED combo for a luminaire from ~2500lm to ~5000lm.

Please feel free to contact me if you have any questions.

You can download the latest simulator below.

Download COB Selection Simulator