LED light, as a power source, has become the major electricity consumption products. The dimming function of LED lights is very important, not only for a more comfortable environment, but also to reduce unnecessary electric light in order to say energy.
Now you may ask, “How to dim the led lights?” Here below we will talk about the main four LED dimming methods.
- TRIAC Dimming
TRIAC, from triode for alternating current, is a generic trademark for electronic component that conducts current in either direction when it is triggered(turned on), and its formal name is bidirectional triode thyristor or bilateral triode thyristor. It belongs to the thyristor family and closely related to Silicon-controlled rectifiers.
Thyristor dimmer has advantages of high precision, high efficiency, small size, light weight, easy operation and so on. Now this dimming method is widely used in LED light dimming. Usually, LED lights only need to use triac dimming driver and triac dimming switch for the LED lights.
The disadvantage for TRIAC dimming is that the dimming performance of thyristor is poor, which usually leads to reduction of dimming range. Because of the attribute of thyristor semi-controlled switch, the thyristor semi-controlled switch can only turn on the current, but cannot turn off the current completely. It still has weak current passing through even if it is adjusted to the lowest level. As a result, there is still a weak luminous phenomenon in LED.
- 0-10V Dimming
0-10 V Dimming is also called 0-10V signal dimming, where a dimmer is used to alter the control signal of the dimming wires from 0-10VDC to alter the LED brightness.
What distinguishes it from thyristor power supply is that there are two more 0-10V interfaces (+ 10V and-10V) on 0-10V power supply. By changing the voltage of 0-10V to control the output current of the power supplier, dimming will happen from 100% light output at 10V and minimum output (off) at 0V.
0-10V Dimming requires a 0-10V dimmer switch to connect with a set of 0-10V dimmer signal lines to LED lights driver for dimming. Although this dimming effect is ideal, wiring is quite complex, which is its biggest disadvantage.
- PMW Dimming
PWM dimming also can be called digital dimming, it can be made by digital programming in the form of wireless network dimming 0-100%. This works by adjusting the duty cycle of the current, resulting in changes to the average current in the string.
PWM is effective for accurate light dimming requirements, as it can handle high dimming ratios at 100 Hz (high frequency, so that the human eye cannot detect the flickering effect), with minimal effects to the LED color/color temperature.
Dimming effect is good, the whole design and installation cost is high, can be used in intelligent occasions which with higher requirements.
- DALI Dimming
DALI(Digital Addressable Lighting Interface) is the most advanced serial digital communication protocol for lighting system control. It has defined as a DALI network, including the largest 64 units (independently addressed), 16 groups and 16 scenarios. Different lighting units on DALI bus can be flexibly grouped to achieve different scene control and management. A typical DALI controller can control up to 40 to 50 lamps, which can be divided into 16 groups, and can handle some actions in parallel. In a DALI network, 30 to 40 control instructions can be processed per second.
DALI is not a real point-to-point network, it is a control ballast instead of 1-10V voltage interface. Compared with the 1-10V dimming, the advantage of DALI is that each node has a unique address code, and the signal attenuation will not occur at a longer distance, but this distance should not exceed 200 meters .
The disadvantage of DALI is the complex signal line design and connection, together with the high cost.