While building an LED fixture, purchasing LED lights, or performing maintenance on the existing fixture, you might need the right LED driver for proper LED operation. And compatibility is crucial while choosing the right LED driver for your application.
The LED driver works by supplying a steady-state current. It prevents the increase in temperature. The requirements of the forward voltage of an LED change with the change in its temperature. The total voltage that is needed to tug into the LED drops.
As the LED becomes hotter, the LED draws in more power. If you leave it unrestrained, then a process of thermal runaway takes place. In this process, the temperature keeps on climbing and results in a burnt-out LED; this is where the LED driver plays its role.
As its output power level matches with the LED thus, it prevents the thermal runaway process. An LED driver does this by supplying the steady-state current. This current keeps the temperature regular by responding to the forward voltage changes.
To clear your doubts, we have explained the working of the LED drive below and in more detail. But before moving on, first, understand what an LED driver is.
What is an LED Driver?
LED drivers are also known as power supplies. It is an electronic device that regulates the power of LEDs or string(s) of LEDs. It serves the same purpose as transformers do for low voltage bulbs or ballasts for fluorescent lamps.
LED drivers provide electricity to LEDs that they need to function and perform well. There are two main reasons why LEDs require drivers:
Rectification
LEDs operate on direct electricity (DC) or low voltage that is 12-24V. Yet, the voltage supply is high (120-277V), alternating current, AC supply at many places. The LED driver rectifies high voltage to low voltage that is covert AC into DC.
Protection Against Voltage and Current Fluctuation
LED drivers to protect LEDs against current or voltage fluctuations. However, voltage changed also cause changes in the current when supplied to the LEDs. Therefore, the output of the LED light is proportional to the current supply of the LED.
There is a specific current range of LEDs within which LEDs operate. We measure it in amps. Thus, when the current is too high to low, it can cause variation or faster degradation of output lighting because of high LED temperature.
To sum it up, LED drivers convert AC (high voltage) to DC (low voltage). Also, they keep the current and voltage flow at their rated range through an LED circuit.
AC to DC Conversion
LED drives to work as an interface between the load (LED) and power supply (line), converting the incoming AC line power 50Hz or 60Hz at 120, 220, 240, 277, or 480V to the regulated output DC.
The design of some LED drivers accept other kinds of sources as well, e.g., POE (Power over Ethernet) or DC power from direct current micro-grids. LED drivers also have immunity against noise such as voltage spikes on the AC line within a fixed design range.
To prevent the output quality of the light source, the LED driver circuit filter out the harmonics. Filtered harmonics show that it does not work only as a power converter. Some manufacturers design LED drivers with some more electronics, enabling them to support bright lighting and precise control over light output.
How Do You Calculate LED Driver?
These are the following factors to consider calculating LED drivers:
Wattage
Wattage is the output power and is in watts (W). The wattage value of LED(s) and LED drivers should be the same. However, for extra safety, the output power of the driver must be higher than LEDs.
If the output power of the driver and LED power requirements are equal, then it is operating at full power. But, the life span of the driver becomes shorter if it is working at full power. The LEDs’ power need is average.
LED drivers are not bound to the number of LED lights they can power. Instead, the total wattage of the LEDs restricts them. For multiple LEDs, designers add tolerance as well. Thus, to cover this, you require output power from the driver to be high.
Output Current (mA)
You require checking the current requirements of the LED(s) you choose while a Constant Current LED driver is in use. The CC LED driver should show that output value. LED data sheets to mention the output current need in milliamps (mA) or amps (A).
There are also selectable and variable output current LED drivers. They either give a stepped value of 350 mA, 500mA, 700mA, or a range like 0 mA to 500 mA. The LED must be within this value range.
Running the LEDs at a lower output current will help in extending their life expectancy. On the other hand, the LED could wear out much faster by using a higher current.
Output Voltage (V)
The output voltage is in volts (V). The constant voltage drivers require the same output voltage as the LEDs. The voltage requirement of each LED is added together
to get a total output value for multiple LEDs.
The driver’s output voltage must exceed the LED’s requirements if you use the CC LED driver.
Dimmable LED Drivers
Both constant-current and constant-voltage LED drivers can be designed with dimming capability. However, this feature must be on the product data-sheet to make that assertion. Don’t assume the product is dimmable if the specs’ sheet doesn’t mention that feature.
The specs sheet of dimmable external drivers mentions the type of external dimmer or other dimming control devices (such as 1-10v dimmers, trailing edge, or TRIAC) they need to work.
As the technologies are rapidly improving, so the best way is to test the dimmable driver combinations. It will tell the acceptable dimming performance, especially before making a huge purchase, and dimmer compatibility charts specific to brands are unavailable.
IP Rating
You must know how much you require your LED driver to be dust or water-resistant. You can see the IP rating in the numerical value of two digits. The first digit specifies the solid object, whereas the second specifies the liquid. A high number of means more resistance.
You should use IP65 rated LED driver if the driver operates where there are chances to contact the water and dust. It will protect it from the ingression of any water and dust projected on it. IP67 or IP68 rated driver is better when requiring something strong against water.
At places like kitchens or bathrooms where there are chances of occasional splashing, an IP44 rating would be suitable. Whereas, IP67 rating indicates the driver is convenient to use outdoor. In dry indoor spaces, you can only use the driver with an IP20 rating.
Life Expectancy
When the brightness of the LED decreases or stops emitting power, the life of the driving circuit expires. As a result, LED drivers have life expectancy known as ‘mean time before failure’ (MTBF) in thousands of hours.
Compare the running level of the driver to work out the advised lifetime. Again, the maintenance cost and time will reduce, and the life span will increase if you run the driver at the recommended outputs.
Size of the LED driver
To decide the size of the LED as per your requirements, you need to know the following things:
- Mains power supply voltage you will use.
- Whether LEDs require a steady current or a steady voltage
- How much total power do LEDs consume in the whole system
- Any other technical factor that can affect the functioning of the LED drivers is the need for potential water exposure or precise color control. Another factor is water-resistant. The IP rating of the LED indicates it.
How to Wire the LED Driver?
First, let’s see how to wire LED drivers for LED strips of a single color. It is straightforward. Connect the +ve and –ve cables of a 240V LED driver to the input terminals of the starter-lead of the LED strip. Your LED strip is glowing now.
To connect with two or more LED strips, join the input terminal of the 240V driver with the output terminal of the connector block. There are dimmable single color LEDs as well. To connect with them, connect the 240V LED driver with the input terminal of an inline LED dimmer.
Safety Guidelines
You can connect one driver with multiple LED products. However, it would be best if you wired the product series instead of parallel. Moreover, disconnect the power until you finish the LED product Installation. The product can suffer irreparable damage if you do; not disconnect the power and connect it.
Before wiring, must ensure the integrity of IP is maintained, either by using fuse boxes or by positioning the LED drivers indoors.
Summing Up
You have read the whole article now; you can decide which LED driver to choose for your LED application. However, please keep in mind the security measures before installation, and you must match the rating with your requirements.
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