The 5 most common dimming methods of LED drive powerTime:2023-07-05 / Read:238
1. Five dimming methods
Front phase cut (Triac dimming)
Rear phase cut (Resistors dimming)
DALI (Digital Addressable Lighting Interface)
DMX512 (or DMX) dimming
2. Dimming principle
2.1. Front phase-cut Triac dimming: use thyristor circuit, start from AC phase Q0, input voltage new wave, until the thyristor is turned on, there is no voltage input. The principle is to adjust the conduction angle of each half-wave of the alternating current to change the sinusoidal waveform, thereby changing the effective value of the alternating current, so as to achieve the purpose of dimming.
2.2. Rear phase-cut Resistors dimming: It is made of field effect transistor or insulated gate bipolar transistor device. Trailing edge phase-cut dimmers generally use MOSFETs as switching devices, so they are also called MOSFET dimmers, commonly known as "MOS tubes". MOSFET is a fully controlled switch, which can be controlled to be on or off, so there is no phenomenon that the thyristor dimmer cannot be completely turned off.
2.3.0-1/10V dimming: There are two independent circuits in the 0/1-10V dimming device, one is an ordinary voltage circuit, which is used to turn on or off the power supply of lighting equipment, and the other is a low-voltage circuit, which provides Reference voltage, and feed back the signal of the dimming level of the lighting equipment, add a constant power supply to the LED driver module, and have a dedicated control circuit, so the 0/1-10 dimmer can also support a large number of LED lighting.
2.4.DALI Digital Addressable Lighting Interface: DALI standard has defined a DALI network, including a maximum of 64 units (with independent addresses), 16 groups and 16 scenes. Different lighting units on the DAL bus can be flexibly grouped to achieve different scene control and management.
2.5.DMX512 dimming: DMX512 is a digital dimming protocol, which divides the light level into 256 levels from 0 to 100%. The control system can realize R, G, B each with 256 levels of gray. Its output signal transmission mode is: RS485 differential signal transmission, which effectively guarantees the reliability of its signal.
3.Comparison of dimming methods
3.1.Leading edge dimming
Advantages: High adjustment accuracy, small size, light weight, easy remote operation and other advantages, occupying a leading position in the market.
Disadvantages: Front-cut dimmers tend to generate a lot of noise, and this dimming method is not recommended for demanding occasions.
3.2.Trailing edge dimming
Advantage: No minimum load requirement, resulting in better performance on individual luminaires or very small loads.
Disadvantages: The cost is high, the dimming circuit is relatively complicated, and it is not easy to stabilize it.
3. 3.0/1-10v dimming
Advantages: simple application, good compatibility, high precision, good dimming effect
Disadvantages: Additional control lines and controllers need to be added.
3.4. DALI dimming
Advantages: precise and smooth dimming, more flexible single lamp control, two-way communication, strong anti-interference ability, fault feedback. Disadvantages: need to add additional control lines and controllers, the maximum transmission distance of DALI is 300 meters, limited by the resistance of signal wires Value and other factors, it is recommended that the actual use distance should be less than 300 meters.
3.5. DMX512 dimming
Advantages: powerful control functions bring rich lighting effects to architectural lighting, night scene lighting, studios and variety show stages.
Disadvantages:special wiring layout and types are required, and certain programming is required to set basic colors and scenes, which The cost of post-maintenance is relatively large.
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