The principle of LED illumination is different from that of traditional illumination. It is based on PN junction illumination. The same source of LED light source, because of the different chips used, the current and voltage parameters are different, so its internal wiring structure and circuit distribution are also different, resulting in various manufacturers. The requirements of the light source for the dimming drive are also different.
Therefore, the mismatch between the control system and the light source and electrical appliances has become a common problem in the industry. At the same time, the diversification of LEDs also poses a higher challenge to the control system.
If the control system and lighting equipment are not matched, it may cause the light to go out or flicker, and may damage the LED's drive circuit and light source.
There are five LED lighting control methods on the market:
1. Front edge phase cut (FPC), thyristor dimming
2, trailing edge phase-cut (RPC) MOS tube dimming
3, 1-10VDC
4, DALI (digital addressable lighting interface)
5, DMX512 (or DMX)
1. Front edge phase-cut control dimming
The leading edge dimming is to use a thyristor circuit, starting from the AC phase 0, the input voltage is chopped, and the voltage input is only available when the thyristor is turned on.
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, thereby achieving the purpose of dimming.
The leading edge dimmer has the advantages of high adjustment precision, high efficiency, small size, light weight and easy remote control. It is dominant in the market, and most manufacturers' products are this type of dimmer.
The leading edge phase control dimmer generally uses a thyristor as a switching device, so it is also called a thyristor dimmer. The advantage of using an FPC dimmer on an LED illuminator is that the dimming cost is low and compatible with existing lines. No need to reroute. The disadvantage is that the FPC dimming performance is poor, usually resulting in a reduced dimming range, and will result in the minimum required load exceeding the single or a small number of LED lighting rated power.
Because of the properties of the thyristor half-control switch, only the function of turning on the current can not completely turn off the current, even if it is adjusted to the lowest, there is still a weak current, and the characteristic of the LED micro-current illuminating makes the thyristor dimming exist in a large amount. After the shutdown, the LED still has a weak luminescence phenomenon, which has become a problem in the current promotion of the wiring-free LED dimming method.
The front-end phase-cut LED dimming driver developed by E-Linker Yilian has solved this problem very well. Through the “C-TURNOFF†technology of the drive circuit, it is easy to avoid the problems of “closed†and “stroboscopic bad lightâ€.
All kinds of lamps matching E-Linker Easy-Link front-phase LED dimming driver can be perfectly matched with other thyristor dimming systems, saving users wire and wiring man-hours, solving thyristor LED dimming matching and not The chaotic pattern of shutting down.
Figure: Front edge phase-cut wiring principle and leading edge phase-to-phase PWM
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