Five kinds of dimming method to let you know the LED lighting
there are five kinds of LED lighting control mode:
1. The phase in the front ( FPC) , silicon controlled dimmer
2. Cut along the phase (after RPC) MOS tubes that move light
3. 1 - 10 v dimmer
4. DALI( The digital addressable lighting interface)
5。 DMX512( Or DMX) Dimming
front cutting phase control dimmer
at the forefront of dimming is USES the silicon controlled rectifier circuit, since communication phase 0, the input voltage chopper, until the thyristor turn-on, the input voltage. Its principle is to adjust each half wave conduction Angle to change ac sine waveform, which changes the effective value of ac current, to achieve the goal of the dimmer.
at the forefront of the dimming equipment has a high controlling accuracy, high efficiency, small volume, light weight, easy to remote operation advantages, such as dominant in the market, the majority of manufacturers of products is this type of dimmer. Cutting edge phase control dimmer generally use the thyristor as switch devices, so also known as the silicon controlled dimmer.
in the LED light on the advantages of using FPC dimmers is: dimming of low cost and compatible with existing lines, without having to cut along the phase control dimmer after wiring. Disadvantage is FPC dimming performance is bad, often leads to the dimming range, and can lead to minimum load is more than a single or a few LED light power rating. Because thyristor switch attributes, only open the function of the current, but can't completely shut off the current, even to the lowest still have weak current flow, the characteristics of micro electric current and the LED luminous with silicon controlled dimmer abound shut final LED chemiluminescence phenomenon still exist, become the current wiring LED dimming way free promotion.
after the cut edge phase control dimmer
after the cut along the phase control dimmer, using field effect transistor ( 场效应晶体管) Or insulated gate bipolar transistor ( IGBT) Equipment is made. Along the cutting phase dimmers after general use MOSFET as switching devices, so also known as MOSFET dimmers, commonly known as & other; MOS tube & throughout; 。 MOSFET is all control switch, can control, can also control, so there is no silicon controlled dimmer can't completely shut off phenomenon. Other MOSFET dimmer than the silicon controlled rectifier circuit is more suitable for capacitive load dimmer, but because the cost is high and the dimming circuit is relatively complex, stability and other characteristics, it is not easy to do the MOS tube dimming is not developed, silicon controlled dimmer still occupied most of the adjustable optical-intensity system market.
compared with cutting edge cutting phase dimmers, cut along the phase after dimmer application on LED lighting equipment, since there is no minimum load demand, thereby on single lighting or very small load to achieve better performance, however, very few of the MOS tube used in the dimming system, generally only make single lamp dimmer switch knob type, the small power cut after that the dimmer is not applicable to engineering. And a lot of lighting manufacturers using the dimmer to adjust light and lamps and lanterns that move light tests. Then will own dimmer products to engineering market, which results in the engineering often appear with silicon controlled dimmer system cut modulated phase modulation of light. This way of dimming mismatch leads to move light flashing, serious will quickly damage the power supply or dimmers.
1 - 10 v dimmer
1 Article 10 v dimming device, two independent circuit, for a common voltage circuit, is used to switch on or off to the lighting equipment of the power, the other one is low voltage circuit, it provides the reference voltage, tell lighting dimming level 0 10 v dimming controller used for fluorescent lamp dimming control on before, now, because on the LED driver module and the constant power supply, and have a special control circuit, so the 0 10 v dimmer can also support a large number of LED light. But application is also very obvious, low voltage control signals need to adding an extra set of lines, the demand for construction is greatly increased.
DALI standard has defined a DALI network, including the largest 64 units ( Can be independent address) , 16 groups and 16 scenarios. DALI bus different lighting unit can be flexible grouped, implement different scene control and management. In practice, a typical DALI controller to control up to 40 ~ 50 lamp, can be divided into 16 groups, at the same time some action to parallel processing. In a network of DALI, a second can process 30 ~ 40 control instruction. This means that the controller for each lighting group, need to manage two dimmer instructions per second. DALI is not really a peer-to-peer network, it is instead of 1 ~ 10 v voltage interface control ballast. Compared with traditional 1 - 10 v dimmer, DALI is that each node has the advantages of the only address code, and feedback, more not like 1 - that move light over a long distance As a signal attenuation 10 v, but engineering practice, this distance is not more than 200 meters.
DALI obviously not suitable for the LED lighting control, a network of DALI can only control the 21st full-color LED lamps and lanterns. DALI is an traditional lighting control, pay attention to a system of a static control, reliability, stability and compatibility. And LED lighting system is much larger than the size of DALI system, mainly the pursuit of artistic effect of lamps and lanterns, the appropriate balancing system of intelligent, which requires the system needs to be greater access to the bus network, a scene of unlimited extension ability and high ability to refresh. Therefore, DALI system in large lighting projects tend to be incorporated into other bus system as a subsystem.