LED driver for my LED

[Voltaic]

I am a newbie.

I have an infrared led, this one
http://www.ebay.com.au/itm/231097780060?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I am trying to choose an led driver to power it with but I am slightly confused.

The led is stated at 10w but has a forward voltage of 4-5v and forward current of 1amp.

So do I need to find an led driver that is 4-5v and 1amp or 2 amps? Could the 10w rating be a mistake or am I adding it up wrong?

With led drivers do I need to match both the voltage and the current to the led or can I get an led driver with the same voltage but more current than the led, or will this fry the led?

 

[Gryd3]

I am a newbie.

I have an infrared led, this one
http://www.ebay.com.au/itm/231097780060?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I am trying to choose an led driver to power it with but I am slightly confused.

The led is stated at 10w but has a forward voltage of 4-5v and forward current of 1amp.

So do I need to find an led driver that is 4-5v and 1amp or 2 amps? Could the 10w rating be a mistake or am I adding it up wrong?

With led drivers do I need to match both the voltage and the current to the led or can I get an led driver with the same voltage but more current than the led, or will this fry the led?

Hi newbie.
You need an LED driver that outputs 1000mA (As stated by the document accompanying the LED)
The driver 'may' vary greatly in the output voltage, as it will change in order to output 1000mA.
Check this:
https://www.electronicspoint.com/resources/got-a-question-about-driving-leds.5/
If you have questions after you read this, let us know.

 

[Voltaic]

Ok thanks I read it (although at my current level I did not understand everything with regard to building power supplies for example.

Also where it says "This site has a pretty goof description of its operation." is it meant to be good? Or does it mean a goof ie. quick description?

So if I am understanding this correctly I have to match the current but not the voltage, but how much can it be out with the voltage?

Do you think I could drive a 10w 1famp 4-5Vf led with an led driver that is 850mA 8-11v?
This is one I have already, would the current be below the threshold for the led to light at all. Would the voltage be too far off the range?

Can I use an led driver which supplies 12v 1a? for the 5v 1amp led.

 

[Gryd3]

Ok thanks I read it (although at my current level I did not understand everything with regard to building power supplies for example.

Also where it says "This site has a pretty goof description of its operation." is it meant to be good? Or does it mean a goof ie. quick description?

So if I am understanding this correctly I have to match the current but not the voltage, but how much can it be out with the voltage?

Do you think I could drive a 10w 1famp 4-5Vf led with an led driver that is 850mA 8-11v?
This is one I have already, would the current be below the threshold for the led to light at all. Would the voltage be too far off the range?

Can I use an led driver which supplies 12v 1a? for the 5v 1amp led.

LEDs are 'current' driven, so you simply need a constant current driver for it. They can be purchased or bought.
The thing is, a constant current driver will adjust the voltage to keep the current at the same point.
The most important thing is that you must have a driver that can output the current you need. As far as the voltage is concerned, you could get a driver that goes up to 60V and it would work perfectly fine with that LED.
I would simply suggest searching for something like a '10W led driver' .. tack on 12V, 120V, or 240V or whatever you want to power it from and you will start finding results.

 

[Voltaic]

Ok thanks, that answered my main question well.

But do you think that the 1a LED could be driven with a 850mA driver and it would run at a lower brightness or would it be too low considering the curve with LEDs and barely light up or not at all?


Also if I was to buy a new driver that was perfect for the 10w 1If 5Vf LED, I would need to buy one that was 1amp 10v (or more) to generate the 10w?

 

[Gryd3]

Ok thanks, that answered my main question well.

But do you think that the 1a LED could be driven with a 850mA driver and it would run at a lower brightness or would it be too low considering the curve with LEDs and barely light up or not at all?


Also if I was to buy a new driver that was perfect for the 10w 1If 5Vf LED, I would need to buy one that was 1amp 10v (or more) to generate the 10w?

I'm sure you'd get a decent brightness out of it running at 850mA, and as far as the 5V reference is concerned, I think the seller screwed up on the data sheet.

 

[Voltaic]

Ok thanks.

Do you think that led is actually 1a 10v 10w or 1a 5v 5w?

If I use a plug pack power supply, how much headroom should I have for driver inefficiencies above the 5w of the actual led?

Someone said that my 4.5v 1a plug pack could drive the led with no resistor, would this be right?
What happens with plug packs when what is connected to them wants to draw more current than they can supply will they overheat and break?

 

[cl10Greg]

The fastest way to find out is to power is with a current limited 5V supply to see if it turns on. You need a certain voltage to turn on the an LED because on the conduction band creation characteristics of semiconductors. Despite them being "current driven" devices they still need enough voltage to activate.

 

[Gryd3]

Ok thanks.

Do you think that led is actually 1a 10v 10w or 1a 5v 5w?

If I use a plug pack power supply, how much headroom should I have for driver inefficiencies above the 5w of the actual led?

Someone said that my 4.5v 1a plug pack could drive the led with no resistor, would this be right?
What happens with plug packs when what is connected to them wants to draw more current than they can supply will they overheat and break?

LEDs are unique devices. They have what's called a forward voltage drop. (Which is advertised at 4-5V)
So, if we built a simple series circuit with a 12V battery, a resistor, and that LED strung together, we would find that when we apply power there would be 4-5V across the LED.
Let's pretend the LED and power supply have no resistance. The only thing in that example limiting the resistance through the LED is the resistor which will have 7-8V across it. We do the math with this voltage to limit the current.
Now, if you use a 'Voltage' power supply only, what happens? Say you put 6V on the LED, the LED drops 4-5V which leaves 1-2V left over... where does it go? Well, if the power supply and LED were perfect, you'd have infinite current, but they aren't. That extra 1-2V gets dropped across stray resistances in the wires, power supply and LED. This would almost certainly allow way too much current through the LED.
That is why you MUST use a resistor when you use a 'constant voltage' power supply. (Which is pretty much ANY wall adaptor you may find)
So, you should either use a constant current supply set to 1000mA, or use a constant voltage supply with a resistor. (Additionally, 10W LEDs can be very bright. You may want to use a covering or some kind of eye protection when working with IR that bright)

 

[Voltaic]

Ok thanks, yes I know that it will be bright even though not visible, I will point it away when testing.


When I test it with the 850mA led driver I guess I'll have to use a thermometre to see if it is working or not since the light probably would not be visible at all. I hope I can determine whether it is working properly with the 850mA driver or not.

What would you say would be a safe distance to look at the ir led from (since it probably won't be visible but still generating ir)?

Also I was planning to use a cpu heat sink without the fan, do you think that would be sufficient?

 

[Gryd3]

Ok thanks, yes I know that it will be bright even though not visible, I will point it away when testing.


When I test it with the 850mA led driver I guess I'll have to use a thermometre to see if it is working or not since the light probably would not be visible at all. I hope I can determine whether it is working properly with the 850mA driver or not.

What would you say would be a safe distance to look at the ir led from (since it probably won't be visible but still generating ir)?

Also I was planning to use a cpu heat sink without the fan, do you think that would be sufficient?

You can use a digital camera to see if the IR LED is working. There is one on almost every cell phone.
I am unsure what a safe viewing distance would be, but it would be best to work in a bright environment.
And I certainly believe a heat sink with no fan will be sufficient.

 

[Voltaic]

I connected it to the 850mA led driver and when looking through the digital camera (using the lcd screen display) there is a slight (I think blue) glow through the camera lcd. Is that expected?

When I connect a multimetre across the terminals while it is running it detects 4.25v

Does that indicate that is what the led is getting, and that is within the range of 4-5v so it should be fine?

 

[Voltaic]

What would happen if I connected it to a 2a supply to try and get 10 watts?

 

[Gryd3]

I connected it to the 850mA led driver and when looking through the digital camera (using the lcd screen display) there is a slight (I think blue) glow through the camera lcd. Is that expected?

When I connect a multimetre across the terminals while it is running it detects 4.25v

Does that indicate that is what the led is getting, and that is within the range of 4-5v so it should be fine?

That 4-5V specified will be across the LED for a range of currents. It's just how the LED works.The fact that you see a faint light from your camera indicates it's working and you've met all of the sellers specifications.

What would happen if I connected it to a 2a supply to try and get 10 watts?

It may power up to full brightness... or you may damage the LED. Remember the seller only stated 1000mA. If you have a spare, I'd certainly encourage you to try, but remember the risks in doing so.

 

[Voltaic]

Ok thanks, yeah I think I'll leave it now since it's working and I glued it to a board etc.

 

[8together5]

850mA is enough.

 

[Voltaic]

Thanks.

When placed in an enclosed wood (seed germination) box how thick would the pine need to be to definitely block any dangerous ir rays?

 

[(*steve*)]

1mm should be fine.