LED Drivers

LED Drivers and other Control Gear

For professional use in LED lighting. Luminaire manufacturers can find a large overview of LED Drivers with varied control options via:

• DALI - Interface
• 1 ... 10V analog Mode
• Button-dimming input (so called Dimming Push Button)

• We offer efficient LED drivers for almost every application.
• Suitable for only one LED or up to 35 LEDs connected in series.
• Various operating modes can be set by dip switches.
• Particularly the LED Drivers of TCI Jolly series offer a master-slave performance of LED Drivers with simple sync cables.
• Whether DALI or 1-10V dimming, via push button or phase cut dimming.
• If desired some of the LED Drivers with conformal coating are available too.
   

Feel free to request one of our LED Driver experts.
We are happy to help. (Your LED Driver Hotline: +49-831-52763143)

Requirements for LED Ballasts / Constant Current Sources

LED lighting products are gaining ground. More and more manufacturers are starting to implement their own ideas in this domain. Along with this it is essential to expose with new technology. To a complete specification of an LED light there are characteristics, which contribute only partially the used LED. Especially regarding life time, dimming and system luminous efficiency appropriate LED Drivers play key initiators in supporting
the stability. These characteristics of LED Drivers are expounded for our customers and readers below.

Overview:

• What are LED Drivers?
• Lifetime
• Dimmability
• Influence on system luminous efficiency
• Conclusion

What are LED Drivers?

In distinction to a constant voltage source, LED Drivers act as constant current sources. They "drive" a constant, resp. controlled or limited current through a LED or LED module. Contrary to in example incandescent lamps it is not possible to drive LEDs with a constant voltage source. Therefore so called current driver circuits are integrated. Correspondingly LED Drivers and LED modules are special operating devices for LEDs for solid controlling. See also constant current source.

Lifetime

LEDs are often advertised with a long service life time. Provided is a sufficient cooling of the LEDs. On the other hand, the operating conditions, for the integrated LED driver in the LED case, must fit. That's why you often can find information like ta = -25 ... 50° C (ta = temperature ambient) or a lifetime of 50.000h. These are only expected if the specific temperature at the tc point (tc = temperature case) < 70°C is kept. Most LEDs are
cooled via their housings, which causes excessive heating for the LED control gear. That's the reason why manufacturers operate their LED control gear in an external housing.

By the way - a high tc value does not automatically indicate that LED Drivers can also be operated at higher ambient temperatures. Basically you can say: the lower the temperature inside and at the environment, the longer the lifetime of electrolytic capacitors will get.

The topic with the switching frequency as lifetime determining property applies more to the switch itself, because the inrush currents of many LED ballasts can be unexpected high and trigger some cutouts surprisingly. For short time, in example 50µs, inrush currents may assume a value of 5-20A. For parallel use of several units cutouts might respond too.

Dimmability

In the past energy-saving lamps or bulbs could be simply dimmed via triac dimmer (phase cut control) but nowadays you have to look closely to when exchanging LED lights. An exchange to LEDs can be achieved if they contain a suitable LED device such as the proven DC-Jolly-MD of the company TCI. But you should know that trailing edge phase dimming does not offer the ability to dim down to zero. A LED Driver like this one is only one example of the universal product family of TCI from Italy. TCI offers a variety of operating devices with their "Jolly-Family", which enables the dimmability of LEDs depending on the selection of the following operation modes:

Push-Button-Mode:

LED Drivers are permanently connected to an applied voltage of 230V AC. A cable is wired with the pushbutton (instead of as in the past the switch) between phase and pushbutton input. So the light can be switched on or off by shortly tipping. If you hold the button pressed, the light will dimmed down or up. 

1 - 10V - Mode:

The LED converter is controlled by a potentiometer (by an activated 1-10V - Interface) with the two relevant connectors. Alternatively, an equivalent DC voltage can be applied.

DALI - Mode:

Some of the LED Drivers contain a DALI input (DALI = Digital Addressable Lighting Interface). A bus system like DALI allows to address every LED light individually.

This is not supported by Jolly family yet, but mentioned for completeness:

DMX - Mode:

A symmetric transfer process with small voltage levels between ±1.5V and ±5V. This technique has to be managed separately to the power line. You often can find that used on stage and at event technology. So far, not many LED Drivers are compatible with such a control mode.

System Luminous Efficiency

System Luminous Efficiency is defined as a coefficient of performance, resulting the amount of energy in light. The results of all efficiencies often gives a disillusioning value. Normally each system consists of

• LED driver (0.7 - 0.9)
• LED according to data sheet (example 115 lm / W)
• LED correction (derating in example 0.9) based on different operating temperature from data sheet
• Optic (ca. 0.9)

Example 1:

Using good LED Drivers with 90% efficiency and other values from data sheet before:

                                                                0.9 * 115 lm/W * 0.9 *0.9 = ca. 84 lm/W

Example 2:

Using cheap LED Drivers with 70% efficiency:

                                                               0.7 * 115 lm/W * 0.9 *0.9 = ca. 65 lm/W

Conclusion:

It is not worth to invest in only high quality LEDs, all components have to "play together".

Other relevant characteristics of LED operating devices:

Before choosing LED Drivers, in addition to efficiency, operating temperature, tc, dimming and the operating current other criterions have to be observed.

• PWM frequency
• Max. Supply voltage
• Interruption secondary possible (test voltage)
• Temperature shutdown
• Surge protection
• Protection class (SELV, I, II)
• Protection type
• PFC
• Cascading
• Standards and Norms

If you need further information not mentioned in the data sheet, please contact us.