Drivers are the Driving Force

But what exactly is it?

If you are a designer and specifying an LED fixture for the first time, or a homeowner wanting to purchase an LED fixture for your space, you may have a few questions. We want to take a moment and clarify how LEDs work and what you will need to know. This knowledge just breaks down anything that may be confusing and of course, we are here for any specific question. Our contact information is below.

Drivers

LED drivers regulate the necessary power ensuring that the LEDS receive the voltage or current based on the LED type in a consistent manner. There are many options of drivers, and we want to take a moment to explain what makes them different. Zaneen will recommend drivers for each fixture, but you can also choose whichever driver works for the product voltage 

 

A driver regulates power to a single LED or multiple LED’s that are connected in a system similar to a daisy-chain. A driver is necessary to ensure our LED works properly and doesn’t get damaged. Since the forward voltage (which is the amount of volts the LED requires to illuminate) of high power LED’s change with temperature, an LED driver has outputs matched to the electrical characteristics of the LED. Therefore, if the temperature increases, and the forward voltages of LED decreases, the driver ensures that the LED receives the consistent voltage or current required to power on, and not over drive the LED which will cause it to burn out. 

 

If you require a product to dim, you must ask yourself the following questions: 

1) What type of power do you require? (DC, AC, Batteries) 

2) What is the main goal of the project? Performance, cost, voltage size etc 

3) Special features required? Pulsing, Microprocessor control… 

 

 

POWER LINE DIMMING

LEADING EDGE / FORWARD PHASE DIMMING

LEADING EDGE, also known as FORWARD PHASE DIMMING is when the dimmer cuts the half cycle of the power sine wave. In the beginning part of the half cycle, the power is off and then turns on. This type of dimming allows for energy savings and is more economical. It is a basic type of dimming and most economical. 

The more you dim the LED, means you are extending the time the power is off during the half cycle. This means, you are using less wattage, the LED is less bright, and you are saving money.
If you want less dimming, the off period will be shortened giving you more power and a brighter LED. 

The reason it is called Leading Edge is because the “turn on edge leads the voltage being applied to the load.”

More economical, usually considered for residential grade.

Dimming_Leading Edge

TRAIL EDGE / REVERSE PHASE DIMMING

Similar to Forward Phase Dimming, REVERSE PHASE DIMMING divides each half cycle of the power sine wave – just in the opposite direction – so the power is in in the beginning and then turns off. 

This method has a smoother turn on and off process and less voltage spikes can occur because the power is switched on at the zero cross point rather than the height of the voltage waveform. 

Dimming_Reverse Edge Dimming
LOW VOLTAGE DIMMING

0 - 10V

An analog device that operates between 0-10V on direct current voltage, also known as DC. At 0 Volts the light is at it’s minimum output, and at 10V the light is at it’s brightest. Why users like 0-10V dimming is because it is quite simple and can be dimmed down to 1% which allows for more precise dimming. When using a 0-10V dimming, a driver would have to be connected to each fixture which does mean additional wiring between the dimming control and LED driver. While other dimmers such as ______, you can use one dimmer for multiple fixtures.  

0-10V

DMX (Digial Multiplex)

Drivers_DMX

This is used to mixing colors control multiples fixtures with different scene

DALI (Digital Addressable Lighting Interface)

News_Dali

Is a digital control signal that drives down separate wires to the main driver. This dimming is used for larger area to control over number of lights. 

 

PULSE WIDTH MODULATION

Drivers_PulseWidthModulation

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DC and AC

Two main types of drivers:
Low voltage DC input power (5-60V)
High voltage AC input power (90-277V)

 

Even if your input is high voltage AC, you can use an additional switching power supply that will allow you to use a low voltage DC input driver.

Often times for smaller areas of lighting, we recommend low voltage DC, however when working with general lighting in a space, AC drivers would most likely be best suited.

Note: As per a new standard, the low voltage class is upgraded to 60V

 

The Output? Constant Current and Constant Voltage

LEDs require a specific balance of current and voltage to perform properly. There are many products that have integral drivers, so when you plug it into the wall the driver convert the standard power from the wall outlet to the necessary output for the specific LED. 
For larger products, the driver may be external to the fixture. The reason for this is mostly due to cost and control over the function of the product. 

 

Example, DICE INVADER 4"

DICE INVADER 4″

Color temperatures: 2700k, 3000k, 3500k, 4000k

Lumens vary depending on the color temperature. 
2700k = 670 lumens
3000k = 690 lumens
3500k = 725 lumens
4000k = 740 lumens

DICE INVADER is ceiling mounted and in the body can the space to contain an integral driver. 

As for dimming, the option is Phase Dimming (which you can choose between Trailing edge and Leading edge), and 0-10V dimming. 

Example, DIXIT R4

DIXIT R4 is a 2W LED with an output of 200 lumens. Due to the miniature size of this fixture, you can guess that the driver is definitely remote. The power supply is 500mA, with a constant current of 120. 
In regards to milliamps, the other 700mA…. ** MORE INFO

Dimming options for the DIXIT R4 is Phase or 0-10V. 

Example, OIKO COMFORT

OIKO COMFORT with the diameter 4″ is 17W, with 2170 – 2390 lumens (depending on the color temperature).

For an installation of 12 fixtures, the total wattage is 204W. It is crucial for the driver you choose to have 10% of space. So you would want to choose a driver approx. 225 Watts. The extra 10% wattage is important because if there is a spike of voltage, the driver and fixtures will not burn out.

Depending on the installation and where the user would like to install the driver (as you will want it accessible for potential maintenance), the size of the drivers may matter. So let’s stay with the OIKO 4″ for the example. If the user would like 400 down-lights in their application, instead of getting one very large driver, it may be better to use a few smaller drivers and locate them in different areas of the building. An important bit of information is that drivers should be approx. 30 feet from the first fixture. The further away from the fixture it is, the potential problem of a drop in voltage, resulting in issues for the proper power to be received at the fixture.  If the driver needs to be further away, a specific type of cable is required so there is no dip in voltage. 

30ft

 

 

 

Of course another thing to consider is the size of drivers. For example, if you’re working on a larger space and require a fixture of 8W but need 300 of them, the total wattage would be 2,400W. It may be difficult to find a driver at this high wattage, in addition, if you do find a driver at this wattage, it may be extremely large in dimension making it difficult to install. So you would be advised to use 5 x 500W drivers to control the 300 fixtures. 

Constant current requires series wiring. 
Constant Voltage drivers are wired parallel wiring.

Generally, when you operate a higher number LED luminaire, you will require less drivers when using constant voltage.4

We're here to help

Our team at Zaneen will advise you on what driver is best suited for your project. What we would need to know is the dimming system you prefer, the quantity of fixtures and lighting calculations.

If you have any thoughts, questions or suggestions regarding this article we would love to hear from you at zteam@zaneen.com 

 

Ciao for now!

Z-Team 

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