I have a question about LED drivers

[bobulak]

Hi everyone. What is the difference between a LED driver and a switching power supply?

So other than the cables is this:

Any different that this in functionality. That is providing power to Cobs. I know they have different specs fore out put Im just curious if they do the same job.

Thanks in advance

 

[Old Salt]

Hi everyone. What is the difference between a LED driver and a switching power supply?

So other than the cables is this:

Any different that this in functionality. That is providing power to Cobs. I know they have different specs fore out put Im just curious if they do the same job.

Thanks in advance

Electrically? Not much, most drivers have current regulation as well as the voltage regulation. The other difference is their resistance to the elements. LED drivers are usually sealed against them, while power supplies usually have open vents.

 

[Elevated Lighting Company]

As @Old Salt mentioned, LED drivers are sealed and ready for the elements. There may also be an efficiency difference.

 

[bobulak]

Thanks for the input. I figure Ill just go with the mean well HLG 240H-C1400B for my DIY cob lighting for my grow.

 

[trueallday]

Hi everyone. What is the difference between a LED driver and a switching power supply?

So other than the cables is this:

Any different that this in functionality. That is providing power to Cobs. I know they have different specs fore out put Im just curious if they do the same job.

Thanks in advance

Hello! There is a massive difference between a switching power supply and an a LED driver. LED (light emitting diode) emit light when current flows through the diode. The actual LED component if simply hooked to a power supply will overload and burn out quickly, sometimes instantly. The LED itself does not limit the amount of current passing through it. There must be a circuit to limit the current to the capacity of the power feeding the LED.

A power supply converts electricity from one voltage to a different one. Sometimes from AC alternating current, to DC, direct current. Household power in the USA is 120v at 60Hz, meaning, it changes polarity, current flow 60 times a second.

Most LEDs use DC current, at a voltage usually less than 20v. Further, you need some way to limit the amount of current flowing through the LED.

A LED supply does the limiting. The LED supply sources a known amount of current, and if the LED is properly sized for current, it will work well and give long life. A power supply simply converts the power and the design assumption is the user will figure out how to properly use the output current. A good supply will have overload and short protection but neither of those will save your LEDs.

You might ask: "Well, how does the LED bulb I buy at a home center or hardware store work, just screwed into a light socket? No power supply, or LED driver?" The answer is the LED current control is built into the bulb. I don't recommend it, but I've taken an number of burned out LED bulbs apart, and find a small circuit board with a variety of components.

Commercial LED grow lights come with the LED supply electronics built in.

I'm not an electrical engineer, and you have to be one to properly design a LED supply circuit and have it work long term. Besides, you're dealing with dangerous voltages at the input. They could cause electrocution and fires. Besides, it's going to be in a wet environment.

If you look at the LED supply you show it probably has UL and CSA certifications, as maybe a IP54 certification. IP54 means it's designed to not fail if it gets splashed with water occasionally.

Quality is usually worth the price.

Good luck!

 

[bobulak]

Thanks guys I appreciate it.

 

[Old Salt]

When I first started in electronics, power supplies were beasts generally without any form of regulation. The voltage out of them could vary by as much as 20%, depending on the age of the components, and the load.

With the advent of semiconductors, specifically zener diodes, tight voltage regulation became the norm.

There are numerous application of current control, LEDs are just one of them. This has become a standard option for many power supplies. It's interesting to note that early current regulation was actually a form of voltage regulation. A small resistor was placed in series with the load, and the voltage across the resistor was compared to a set point. This comparison was used to control the output stages of the power supply.

Now let's look at an LED. It can be thought of as a resistor, battery, and lamp, all in series. The battery can be thought of as a 0.3 - 0.7 volt voltage source. The actual value depends on the manufacture of the device. For current to flow through the LED, this voltage must first be overcome. Then the resistor comes into play, reducing the current through the LED. As the voltage applied to the LED increases, so does the current through it, and it starts emitting light. The current and light continue to increase with the applied voltage, until it becomes too much for the LED, and it fails.

The LEDs in most home electronics are powered by far too much voltage, and have a resistor placed in series with them to limit the current. This would be very inefficient for our LED light fixtures, as the extra power would be converted to heat. This is why regulated power supplies are used. These regulated power supplies are designed to meet the requirements of LEDs, and have been given the name drivers. If you were to measure the voltage across a LED connected to a current regulated power supply, you would find that it varied directly with the current.

Any regulated power supply with the correct voltage and current output can be used to power LEDs.

A LED driver is simply a power supply designed to meet the specific requirements of LEDs.

This is material I started teaching over thirty years ago. It's funny how it applies to horticulture, as well as radios, radars, and computers.