Different dimming

LED is different than traditional lamp, it relies on P-N dimming, same LED lamp,due to the LED chip differs,work voltage,curent specification is different, so its inner structure and circut distribution is different. 
Hence each LED factory's light to dimming driver is different, the dimming system's compatibility with LED lamp source became a chanllenge.
If it doesn't match, it cause light goes down or flickering sametime cause damage to LED driver and the light.
There are 5 types of dimming:
1. FPC (Leading edge) dimming- Thyristor
2. RPF(Trailing edge)MOS dimming-transistor  
3.0-10V dimming
4. DALI( Digital address finding port)
5. DMX 512 Dimming
 FPC(Leading edge):
 
FPC dimming is controllable silicon circuit, the AC phase 0 began, until the input voltage chopper, thyristor, only input voltage. Its principle is to adjust the current each half wave conduction angle to change the sinusoidal waveform...  hence to adjust AC current's effective value to realize the dimming.
It has the advantage of 1. high adjusting accuracy,effective, small size, light weight, easy to control in distance. It is one of the leading dimmers. Most of the dimmers are the FPC type. Because the FPC dimmers usually use thyristor as a switch components so we call thyristor dimming.
 When use LED lamp to be compatible with FPC dimmers, the advantage:
Lower cost, compatible with existing electric wiring, no need to re-arrangement on wiring .
The disadvantage:
FPC dimming function is not very functionable, sometimes the dimming range is less, and also request each minimum load should exceed one pcs or some LED lamp its self' Nominal power. Example can't put 9pcs of 2W LED Lamp to a 20W ～300W dimmer but you can use a 11Pcs of 2W LED Lamp to a 20W~300W Dimmer. Because the thyristor's own feature is to let the current switch "ON" only. can't totally switch "OFF" the current. Even though when you dim to the lowest, still current is passing through. But LED can light on when there is a little current.
That is one of the challenge when customer doesn't want rearrangement of the wiring and doesn't want change dimmers.
Some of the good thyristor dimming driver can solved this problem, it use the driving circuit"C-Turn OFF" technology to avoid "not switching off" and " flickering cause the light off".   hence to get the "problem of dimming compatibility" and no "switching off" solved.
 
Traling edge dimming(Transistor dimming)
It uses FET( field-effect transistor) or IGBT( Insulated Gate Bipolar Transistor) to make from.  Trailing edge usually use MOSFET as a swtich component,
so we call MOSFET dimmers also. MOSFET is full controlling switch, can control "ON" can also control"OFF" so it doesn't have problem of not totally switching off.
MOSFET dimming is more suitble for capacitive load dimming than the Leading edge. BUT because its cost is high and the dimming circuit  is a bit more complicated,not easy to make ... features, it is not
developing well as Leading edge do.
Compare with leading edge, the trailing edge is used on LED lamp, it has no minimum loading requirement, so it can be used on one single LED lamp or small loading to realize the dimming. Again the MOS is seldom used on dimming system, i is only used knob type of single lamp dimming switch. This type of dimmer is not applied for project market. It caused projects need leading edge system to adjust trailing edge dimming driver cases.  If this type is not compatible, it will also hurt the driver and the dimmers.  
 
 


1-10V Dimming
1-10V Dimming has two seperate circuit,,one is the odinary voltage circuit, it is  used to connect or disconnect Lamp's power. Another is low voltage circuit, it provide refering  voltage, tell the lamp dimming level,
0-10V dimming controller is used for CFL dimming, now as we add stabilized power on LED Lamp and has speciallized control wiring, so 0-10V dimmer also can support a lot of LED lamps.
But it also have obivious disadvatage as we need add an extra electric wiring for low voltage control signal. It has much more requirement on the construction.
 
DALI Dimming-
Not to explain here
DMX512 Dimming
Not to explain here.  

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