Driver Circuit for 10Watt smd Led

Hi,

I have a 10 Watt smd led and I want to drive it from a 12volt lead acid rechargable battery, does anybody have a circuit please or an ebay link to a suitable driver.

Thanks In Advance
Rizzy

depends on LED specs.

Hi Sunny,

All I know is that it is a 10 watt smd, it was a purchased 230 volt floodlight but I want to run it off a battery for a portable work light, could I hook it up to my bench power supply and slowly turn up voltage and current to see how it performs, I have been told that they are 12 volt dc and around 800ma.

Thanks
Rizzy

rizzy_dascal said:

could I hook it up to my bench power supply and slowly turn up voltage and current to see how it performs

Click to expand...

You will surely burn the component to see that exceeded some specification, especially if it is not effectively connected to a sink. Semiconductor components as this do not have a body mass that absorbs heat slowly. I recommend you take a look at SOA graph that comes in dataheet.

Hi Andre,

No data sheet came with the floodlight, just instructions how to wire up to 230v , I have removed the 230v driver, I just have the Smd led.

Thanks
Rizzy

rizzy_dascal said:

Hi Andre,

No data sheet came with the floodlight, just instructions how to wire up to 230v , I have removed the 230v driver, I just have the Smd led.

Thanks
Rizzy

Click to expand...

My bench and my study are illuminated by SMD LEDs. I bought 10V LEDs and put 3 of them in series and I drive them by the switcher from my old printer that gave 40V 1A, I changed it to a current source of 800mA.
There are 10W SMD LEDs for 10V up to 40V. My guess is that yours is the 40V LED. To check connect the LED to your 12V via 100 to 470 ohm resistor, making sure you got the right polarity. If the LED gives light then it is 10V, if you get no light at all it is more than 10V and you have to repeat the test on 48V source.
If your LED is 10V then you will have to look for a linear LDO variable regulator and wire it as current regulator following the circuit in the datasheet. You will be able to use (discharge) the battery down to 11V before the light will go out.

You need to measure the Forward Voltage.

To measure the Vf, you need a good [calibrated] multi-meter, a good* DC power supply[the actual voltage is not so important - somewhere between 5 and 12V; a 9V battery is usually a good choice], an appropriate resistor, and the LED.

Use the Guru [http://ledcalc.com/]to find the resistor value - use a current of about 1/2 the maximum current - in your case use 1/2 of 700mA. The value is not critical.
Use the average [of the Vf range] or middle value for the voltage drop. Click on the '?' beside "Voltage Drop Across the LED" for some suggestions, if you are unsure.

Make sure to enter 1 as the number of LEDs connected..

Set the multi-meter to the 2VDC [or something similar] range if you believe the Vf is under 2V
else
Set the multi-meter to the next higher range if you believe the Vf is over 2V



see http://ledcalc.com/ for more
Connect per the diagram -- when the LED is on, the voltage shown on the multi-meter is the Vf

Although the personal experience is a valuable resource, I keep believing that the problem still lack of more information about the device. I already burned an array of LEDs of a strobe system just applying a continuous current, due it was thermally dimensioned to operate in pulsed mode. Despite the brightness did not seem to exceed the rated for device, the heat generated in the components made them burn in seconds.