CA452001EN - March 2015
LED Driver Selection
Why is a driver module required?
An LED (Light Emitting Diode) is a solid state device, or
semiconductor, which converts electricity passed through it into
visible light. To maintain the light output, colour, efficiency and
maximise the life of an LED, three factors must be controlled:
1. The manufacturing process and composition of the LED itself
2. Thermal management of the heat generated by the LED
3. The electrical supply to the LED
The driver is the device used to control the electrical supply to the
LED. The majority of luminaires in the Eaton’s LED ranges require
an LED driver. Some luminaires are supplied complete with the
appropriate driver, whilst others indicate on the product pages if a
driver is needed.
There are essentially two basic types of driver, those supplying a
constant current and those supplying a constant voltage. These
are then subdivided by other capabilities such as dimming or
Within the Eaton’s range there is a wide selection of drivers
offering different features and characteristics to provide the right
product for the application. There is a choice of constant current
or voltage outputs, different levels of Ingress Protection, Dimming
methods and Colour Changing versions as well as different
Constant Current Drivers
The majority of luminaires operate on a constant current, however
not all constant current LEDs operate on the same current. It is
therefore important to note the recommended current for the
luminaire and select the appropriate driver. It is possible to operate
luminaires at a lower current than recommended though this will
reduce the light output and can affect the efficiency. If the current
is too high it may cause premature failure of the LED.
When connecting multiple luminaires to the constant current
drivers they must be wired in series.
Constant Voltage Power Supply Units
Some of the LED luminaires require a constant voltage, usually
12V DC or 24V DC. When connecting luminaires to these constant
voltage drivers they are wired in parallel.
A selection of constant current dimming drivers are available
with different switching modes and control language protocol,
eg retractive switch, 1-10V, DMX and DALI
Colour Change Drivers
LEDs are often associated with colour options and the ability
to change the colour emitted from the same luminaire. This is
achieved by mixing the output from an array of individual Red,
Green and Blue LEDs or specialist ‘Tri-chip’ LEDs to generate any
colour of the visible spectrum. These products are referred to as
having the ‘RGB’ colour option. Several such drivers are included
in the range for various budgets, most are DMX compatible.
‘DMX’ is the type of software protocol used. (Not all luminaires
are offered with RGB colour change options).
Some drivers are multi-channel, typically 3 channel. For RGB
products each channel is dedicated to a colour, Red, Green, Blue.
For fixed colour product the number of luminaires connected
should be split evenly between each channel, eg for LS-PBX27
the maximum number of 1W LEDs it will operate is 27, split 9 per
3 Channel fixed output multiple connection