The five main dimming methods of LED lights

1. 1-10V dimming: There are two independent circuits in the 1-10V dimming device. One is an ordinary voltage circuit, used to turn on or off the power to the lighting equipment, and the other is a low-voltage circuit, which provides a reference Voltage, tells the lighting equipment dimming level. 0-10V dimming controller was commonly used for dimming control of fluorescent lamps. Now, because a constant power supply is added to the LED driver module and there is a dedicated control circuit, so 0 -10V dimmer can also support a large number of LED lighting. However, the application shortcomings are also very obvious. Low-voltage control signals require an additional set of lines, which greatly increases the construction requirements.

 2. DMX512 dimming: The DMX512 protocol was first developed by USITT (United States Institute of Theater Technology) into a standard digital interface from the console to control the dimmer.  DMX512 transcends analog systems, but cannot completely replace analog systems.  DMX512's simplicity, reliability (if installed and used correctly), and flexibility make it the protocol of choice if funds allow. In practical applications, the control method of DMX512 is generally to design the power supply and controller together. The DMX512 controller controls 8 to 24 lines and directly drives the RBG lines of LED lamps. However, in building lighting projects, due to the weakening of DC lines, it is required to install a controller at about 12 meters, and the control bus is in parallel mode. , therefore, the controller has a lot of wiring, and in many cases it is even impossible to construct.

 3. Triac dimming: Triac dimming has been used in incandescent lamps and energy-saving lamps for a long time. It is also the most widely used dimming method for LED dimming. SCR dimming is a kind of physical dimming. Starting from AC phase 0, the input voltage chops into new waves. There is no voltage input until the SCR is turned on. The working principle is to generate a tangential output voltage waveform after cutting the input voltage waveform through the conduction angle. Applying the tangential principle can reduce the effective value of the output voltage, thereby reducing the power of ordinary loads (resistive loads). Triac dimmers have the advantages of high adjustment accuracy, high efficiency, small size, light weight, and easy remote control, and dominate the market.

 4. PWM dimming: Pulse width modulation (PWM-Pulse Width Modulation) technology realizes control of analog circuits through on-off control of the inverter circuit switch. The output waveform of pulse width modulation technology is a series of pulses of equal size that are used to replace the desired waveform.

 Taking the sine wave as an example, that is, making the equivalent voltage of this series of pulses a sine wave, and making the output pulses as smooth as possible and with less low-order harmonics. According to different needs, the width of each pulse can be adjusted accordingly to change the output voltage or output frequency, thereby controlling the analog circuit. Simply put, PWM is a method of digitally encoding analog signal levels.

 Through the use of high-resolution counters, the occupancy ratio of the square wave is modulated to encode the level of a specific analog signal.  The PWM signal is still digital because at any given moment, full-scale DC power is either fully present or completely absent. A voltage or current source is applied to the simulated load in a repetitive sequence of on or off pulses. When the power is on, it is when the DC power supply is added to the load, and when it is off, it is when the power supply is disconnected.

 If the frequency of light and dark exceeds 100Hz, what the human eye sees is the average brightness, not the LED flashing.  PWM adjusts brightness by adjusting the proportion of bright and dark time. In a PWM cycle, because the brightness perceived by the human eye for light flickers greater than 100Hz is a cumulative process, that is, the bright time accounts for a greater proportion of the entire cycle. The larger it is, the brighter it feels to the human eye.

 5. DALI dimming: The DALI standard has defined a DALI network, including a maximum of 64 units (can be independently addressed), 16 groups and 16 scenes.  Different lighting units on the DALI bus can be flexibly grouped to achieve different scene control and management. In practical applications, a typical DALI controller controls up to 40 to 50 lights, which can be divided into 16 groups, and can process some actions in parallel. In a DALI network, 30 to 40 control instructions can be processed per second. This means that the controller needs to manage 2 dimming instructions per second for each lighting group.