LEDs (Light Emitting Diodes) are semiconductor devices to convert electricity to light and are inherently dimmable. As LED technology (light source) continues to advance, more lumen output can be achieved with even less input power. Compared to Traditional Lighting, LED lighting is more complicated in terms of supply chain and has more electronics involved. Thus, LED dimming becomes a practical needs as the LED technology continues to evolve.

It's now more common to find a dimmer control in LED lighting than a few years back. Since there are many types of LED dimming technologies (both Wired and Wireless), it’s good to have a basic understanding of different types of LED dimming in order to understand the difference between AC Phase Dimming or Mains Responsive Dimming and other approaches. (Below) Typical AC Output Waveform of a TRIAC Dimmer. It's easy to see that's not the familiar sine-wave waveform.

  

The easiest way to recognize AC Phase Dimming is by looking at how the LED drivers are connected to the Dimmers (or the Control Units like a PC). For DIMEZE™ type of AC Phase Dimmer, it only has 2-wires for connection: One for connecting to the AC Live wire and the other for providing dimmed Live connection to the Live input of subsequent LED Driver(s). The Neutral wires of the LED Drivers are commonly connected together for a return to the Main Circuit Board. As both terminals of Phase Dimmers are connected to the Live Wire, some Electricians say this type of connection as “Live-In / Live-Out”. Note we do not distinguish polarity during wiring for our phase dimmers.

An AC Phase Dimmer controls the Live input and manipulates the actual input power / input voltage into the LED Drivers in the form of a Chopped Sine-Wave, preferably in the Trailing-Edge phase-cutting format for LED lighting. The Phase Dimmable LED Driver(s) then adjust the light intensity level and regulate the LED driving current accordingly. How accurate can the LED Driver adjust and stability to regulate the driving current are the key performance indicators of the LED Drivers. How deep can the LED Drivers dim is what we describe as Deep Dimming Compatibility. Thus, AC Phase Dimmers operate at Line Voltage (110 / 220Vac).

Although the remarkable difference in their waveforms, when measured at the DC output of the LED Driver, the chopped sine wave has no impact on the DC at maximum brightness level. (Below left) The DC output measurement (35.31V) at LED driver when no phase dimmer is connected. (Below right) DC output measurement (35.28V) at LED driver when a phase-cut (TRIAC) dimmer is connected, basically no difference.

   

 

Read on
 

What's the Difference Between Dimmable and Non-Dimmable Lamps?

In a nutshell, Dimmable LED lamps are capable of handling the input power reduction (as dimmer dims) and steadily reduce the LED driving current to produce the dimming effect. However, non-dimmable LED lamps CANNOT. Thus, dimmable LED lamps can be used in the On / Off (non-dimmable) circuit, but the reverse is usually not true. When the line voltage drops below a certain level, it appears to be a power failure to a non-dimmable lamp, which will be switched off suddenly.

What's the Requirement for Dimmable Fixture?

To achieve LED dimming, the LED bulb itself or the driver (power supply) must support dimming function. In other words, replacing the LED driver with a dimmable LED driver would make a non-dimmable LED lamp become a dimmable version. See our video for implementing a dimmable function with a malfunction LED lamp.

What Happen if I use a Dimmer to Dim a Non-Dimmable LED Lamp?

“Can the dimmer also dim non-dimmable LED lamps?”  From our experience, grudgingly using a dimmer on non-dimmable LED lamps may somewhat reduce the brightness level. But eventually, the lamps would misbehave (flickering or even popping up at low frequency) and switch-off.​

What's "Depth" in LED Dimming?

Compared to Incandescent & Fluorescent lamps, the flickering issue with LED is much more noticeable because LEDs exhibit very fast luminous response to minor fluctuations of the LED driving current. Thus, the Dimming Range (Depth) of Dimmable LED driver is always the first consideration for LED dimming.


What Do They Mean by a "Flicker-free" LED Driver?

“Flicker-free” LED drivers refer to dimmable drivers that are designed for driving the LEDs at low brightness level. Then, the next question is how "low" is low? In practice, very often an LED dimmer controls more than a single lamp or more than one types of lighting fixtures, which means that it's likely the dimmable equipment from multiple manufacturers (individual devices in the system) may not support the same level of dimming range. Unfortunately, this is only found when all the lamps are connected together or in the field installation stage. In cases like this, it's recommended to deploy DIMEZE™’s MIN-LEVEL-SET feature to fix an acceptable System Dimming Range to achieve flicker-free LED dimming. See how Minimum-Level-Set works here.


What's a Phase Dimmable LED Driver?

A phase dimmable LED driver from the market has an unknown dimming performance; Phase dimmable LED drivers are also commonly known as "TRIAC dimmable LED drivers". However, as we point out that although TRIAC dimmers operate by phase-cut technology, they are not suitable for reliable LED dimming. See comparison video to illustrate the difference between TRIAC and Digital LED dimmer.

What Should We Expect for LED Dimming?

Since there is not yet a ready market standard for dimming performance, any product with its brightness level adjustable can be termed as “Dimmable” product. In order to set an expectation on LED dimming effect, we utilize the information from the IESNA Lighting Handbook 9th Ed.:

“At low levels, the human eye would enlarge the pupil to allow more light to enter the eye. This mechanism creates a difference between the measured light (by light meter) and the perceived light (by the human eye). A lamp that is dimmed to 20% of its maximum measured light output is perceived as being dimmed to only 45%.”

For our discussion, we shall refer 20% or below of the maximum measured light to as “Deep Dimming”! Read on
 

How About the LED Dimmer?

     For AC mains powered LED dimmable lighting, the dimmer manipulates the AC waveform and controls the phase dimmable LED driver(s). Thus, the dimmer stability directly affects the whole LED driver operation. 


Same Lamp, Different Dimmers! Very Different Results!!
 

So far, we've mentioned that an LED driver is critical to LED dimming performance. In the following example, we choose to use the same dimmable lamp (i.e. exact same LED driver) to illustrate the significance of an LED dimmer. Using the same Tune-able downlight with different dimmers (Philips SED-200A vs. DIMEZE™ DZ2G450DIAL), two very different dimming performance is captured to the right.  The right photo shows the lowest dimming level by SED-200A, while the immediate left photo shows Deep Dimming performance achieved by DIMEZE™ Digital LED Phase Dimmer. This example of achieving two very different dimming performance with the same LED driver (the same LED Lamp) shows that dimmer is another critical factor for LED Deep Dimming performance. See the comparison video to understand difference between Deep Dimming and. “Dimmable” Effect with the same Downlight

Deep Dimming performance by DIMEZE™ With the same LED lamp, the Lowest Dimming Level by SED-200A

What's a Phase-Cut Dimmer?

Phase-Cut dimmer blocks the input line for a portion of the line cycle, which inhibits the average energy transferred to the lamp load and hence, the output brightness. Both TRIAC dimmer and DIMEZE™ LED dimmers operate by phase-cut dimming principle. However, they are very different in design.

TRIAC dimmers operate on leading (forward) phase-cutting methodology, while DIMEZE™ Digital dimmers are known as “Universal Dimmers” because it has the option to support both leading and trailing (reverse) phase-cutting methodology. Designed for Incandescent and Halogen bulbs, when used with LED Lighting, TRIAC dimmers are usually associated with the following problems:  

[Above] TRIAC dimmers are commonly available in market; on the manual, it says clearly the dimmers are for Incandescent load only.

# 1 / Performance Inconsistency Read On
# 2 / Shorter Product Lifespan Read On  

See how TRIAC dimmers are different from Digital LED dimmers here

Sometimes even with a great lighting design, designers should realize that in the local market, most of the retrofitting scenario only has the Live- wire for the dimmer switch to connect and the Neutral wire is shared or connected to the lamps next rooms. Thus, if the designer selects a dimmer that requires individual Neutral wire connection would be problematic in field installation or the design just can’t be implemented.

The schematics of our Evaluation kit shows "Single-Live and Common-Neutral" connection or “Live-in, Live-out”, also known as “Hot, Dimmed Hot” in the US. Our EV kit is great for mock-up or field evaluation; for interested customers, please contact us for our evaluation kit or samples for evaluation. Contact Us

Interaction Between LED Dimmer and LED Driver

In conclusion, how should we understand the role of Dimmer and Driver in LED Dimming? First, we must remember dimmer and driver always work hand-in-hand. The first condition for LED dimming is obviously the driver, since if the driver is not dimmable, the LED lamp won’t dim; if the dimmable driver design is not good, the dimming performance would be prompt to problems.

From LED dimmers point-of-view, a quality dimmer only reflects (not changes, nor improves) the driving capability of the LED driver at low brightness level. As a system controller, the dimmer determines how low can the LED driver dim; there are cases when a LED driver has a "buck-boost topology" design in such a ways that regardless of any further line voltage drop, the driver raises its internal voltage and keep it at a certain minimum level (from the lamp perspective, the brightness level would not be able to dim anymore).

For deep dimming, a key dimmer performance indicator is the Minimum-Load-Required by the dimmer itself. As LEDs are very sensitive to the changes of the driving current from the driver, which ultimately is powered through the dimmer, very stable system performance by both the dimmer and the driver at low brightness level (when the current is already very small) is the key to project success.

“Deep Dimming Compatibility” shall be the real target to look for in practical applications. When we refer to “Deep Dimmable Compatibility”, we refer to the following:

     • “Quality Dimmer” + “Quality Dimmable Driver” = “Deep Dimming Performance”
     • “Quality Dimmer” + “Poor Quality Dimmable Driver” = “Poor Dimming Performance”

While there are numerous LED driver manufacturers in the market, we're glad to recommend Meanwell PCD series (AC Phase-Cut Dimming) to work with DIMEZE™ Digital Phase LED Dimmers. See our product video here. To further illustrate that different "dimmable LED drivers" perform differently, please see this comparison video between Meanwell and HEP TRIAC Dimmable LED Drivers for more ideas.

 

To choose the right dimmer device, it’s necessary to understand correctly the MAX and MIN loading requirement of the device in order to ensure product safety and to have consistent performance as the number of lamps increase or decreases during installation.

• The MIN Power states the minimum power the dimmer circuit itself requires for normal operation and it also determines how low the lighting system can be dimmed in a 2-wire dimmer system. Sometimes, users would find that LED flickering happens after removed the lamps from the connection, learn more about this in this video.

 

• The MAX Power determines how many lamps can be connected to the dimmer without causing electrical stress or potential faults. While DIMEZE™ dimmer series has the MAX rating of 450W, to determine the maximum number of lamps can be connected is not as simple as dividing the overall rated power of the dimmer by that of each lamp. The simple logic of “450W / 10W per Lamp = 45 Lamps Connected” does NOT apply! Read on

In practice, it's common that electrician or end-users would find a LED dimmer burnt-out after used for a while. One of the reasons for such failure is due to LED dimmer overload, which usually means too many LED drivers are connected together to the same dimmer. While the 450W power rating for the DIMEZE™ LED dimmers sounds like "too much" for the average LED bulbs or a downlight that consumes less than 20W, we should remember about power de-rating for the devices in installation. Instead of finding out how many LED drivers can be connected by trial-and-error, we should consider the Inrush Current parameter of the LED drivers.
 

[Above / Data extracted from Meanwell Product Marketing materials on PCD series, which is an AC phase-cut dimmable LED driver series; Meanwell website: www.meanwell.com]

The maximum inrush current that the DZ1G450CAPS can handle is 35A, which seems to be a big number. However, when we look up the maximum inrush current for the LED drivers, you may find the number can be as high as 10A or more (e.g. Meanwell PCD-16-xxxB series has a 10A figure for the max inrush current). If we use this number for a rough estimation, that means we may only connect 2 to 3 units of PCD-16-xxxB to a single DZ1G450CAPS. In terms of power rating, this would mean around 3x 16W or 48W vs. the 450W of the DZ1G450CAPS.
 
However, for best practice, electricians are recommended to reduce the numbers of LED drivers connected to the dimmer and use a bigger power rating driver instead. In our example, using 3x PCD-16-300B (48W) would result a Maximum-Inrush-Current as high as 30A; on the other hand, for similar power range, if we only use a single PCD-40-xxxB (40W) or PCD-60-xxxB (60W), the actual maximum inrush current stress posted onto the LED dimmer would be largely reduced to 11A or 13A respectively! Thus, from minimizing the Maximum-Inrush-Current point-of-view, our suggestion is to "Always reduce the number of LED drivers connected to the LED dimmer and select a single LED driver with suitable power rating (include proper de-rating) if possible".
 
Back to the scenario at the beginning, when electricians found the LED dimmers burnt-out, one of the suggestions is to split the lighting circuit and install more LED dimmers. But in reality, sometimes it is not an easy option to implement a new set of wiring for additional dimmer switches. Alternatively, electricians may review and design the overall system configuration to reduce the number of LED drivers and or both replace the LED dimmer with a higher power rating. Choosing high power rating modular switches that fit into a single wall plate can make the re-wiring much easier and save making a new hole in the wall and is a good alternative to explore!

Before choosing the LED driver from a supplier product catalog, the 1^st step is always to understand the lighting equipment itself. The most obvious question is “Does it require an External LED Driver?”

Products with Integral Drivers

Typical LED retrofit application (popular lamp base for screw-in: E27, E14, A19, GU10, MR16 etc.) all have integral LED driver ICs that provide the necessary constant current for the LEDs inside the lamp; the dimming performance and the compatibility with the dimming control device / dimmer of such types of products would be determined by the capability of the integral LED driver (driver IC) inside. While it’s more common to have integrated LED drivers to the lighting equipment now, the Electricians or End-Users should remember that products to be directly driven from the AC mains must pass proper Safety Regulation (Critical Factors: EMI/EMC, Efficiency % (ƞ), Power Factor etc.) and must be provided with proper Heat Dissipation to avoid overheating during operation. Additional consideration on Years of Warranty and International Protection Ratings (IPxx) should also be checked. See the actual dimming performance of popular off-the-shelf retrofit lamps here or dimmable LED filament bulbs here.
 

• High CRI MR16 LED lamps that are popular for Halogen replacement would have external “electronic transformers” to provide a step-down function from the AC Mains Voltage to the 12Vac (in the below-left photo, see the 2nd line from the top "7W 12Vac"). The 12Vac that is further regulated by the LED driver IC inside the MR16 light bulb to provide proper driving current for the LEDs. The dimming function actually comes from the LED driver IC inside and must be available with the light bulb before our LED dimmers can work. (See 1st line "Dimmable".)

           
 

• Above right is a 28W Phase Dimmable LED driver designed for a 300mm Ceiling Lights sitting inside the lamp.

 

• Below are AC Driverless Modules that can be connected and dimmed by our LED Dimmers directly (220Vac). Note proper heat sink should be used according to information available on the product datasheet.

         

External Drivers Needed

If a lighting product requires an external LED driver, we can further classify it by the type of outputs needed to drive the lamp load, namely, Constant Current (CC) or Constant Voltage (CV). As the name implies, a Constant Current (Constant Voltage) LED driver would have its output voltage (output current) proportional to the power rating of the LED lighting equipment. Note these two types of LED drivers are not interchangeable! Typically, except the LED strip lights and the Electronics Transformer mentioned above, most of the LED lighting equipment require Constant Current (CC) drivers to work. 

Constant Voltage LED Driver

• While it’s possible to design Constant Current (CC) LED drivers to match a LED strip, in practice the Constant Voltage (CV) LED drivers (or even Standard Power Supply) are used due to the fact that we do NOT need to match the output current for the LED strip length (a variable). As long as the operating voltages of the Driver and the Load match, more (less) current would be drawn from the driver when we increase (decrease) the load to the point beyond which the driver is able to support. The LED strip lights have small resistors throughout the strip to absorb the potential difference and provide a current-limiting function. The main consideration for the CV LED driver then boils down to matching the Output Voltage (i.e. 12V, 24V and 48V), Power Factor, Efficiency (ƞ), IP Code and the proper Driver De-Rating to match with the electrical load. If a dimming function is required, the next question is about the dimming interface, such as phase-cut dimming or 1-10V dimming, etc. For a comparison of phase-cut dimming performance using a CC LED driver and a CV LED driver, please see this video. 

 

• In below product photo, the 2-wire 1-10V control terminal is shown on the top right of the 60W 24V Constant Voltage LED Driver

         

Constant Current LED Driver

• Recessed LED Downlight is a typical application of Constant Current LED drivers since the LED Downlight itself is usually composed of a metallic fixture, LED board, secondary optics, and heatsink. The downlight usually has a much higher power consumption than the retrofit bulbs. The typical specification on a downlight would state the power (W) and the driving current (mA). As the 1 ^st approximation, simple calculation (E [V] = P [W] / I [A]) would indicate the output voltage required for the LED driver (or the input voltage of the downlight). In below-left product photo, the downlight consumes 5W and requires 350mA driving current, which means the operating voltage is around 14.3V; below-right shows another 350mA downlight that has an operating voltage of the 35.7V (= 12.5W / 350mA); the desired LED driver should then have an Output Voltage in that range, providing the Rated Power and the Driving Current. In above example, since both downlights consume 350mA driving current, the voltage is about 2.5x higher for the 12.5W downlight than the 5W downlight.

         
 

• When matching a LED driver for a lamp on-hand, the typical suggestion is to have the load power rating to be around 70% - 80% of driver rated power. If a dimming function is required, the percentage may be 80% - 95% (subject to the lamp load type and actual working environment); for example, for a 16W (Meanwell PCD-16-700B) LED driver, 80% of the rated power is 12.8W for the lamp. The output power of the LED driver MUST ALWAYS exceed the load; if more than one lamps are required per driver, additional consideration such as Inrush-Current must be considered. ​

 

• Contrary to the name suggested the following current measurement shows the driving current going into the LED continues to be reduced as we dim the phase dimmable Constant Current LED driver. Originally, the output current matches with the Rated Current of PCD-25-350B (350mA), then the current continues to drop as we start dimming (see video).

          
 

• Multi-Power LED Driver  (aka Selectable Output-Current LED Driver) is an interesting offer from the constant current family. A practical drawback of CC LED drivers is that it may be difficult to find a suitable LED driver in the market to match the input V/I of a lamp on-hand. The selectable output current approach allows the installers to set the output current by using a DIP switch in a wide operating voltage range. It's also common for such multi-power driver to have a 1-10V control interface for brightness control; to see how DZ1G1TEN works with such Multi-Power LED driver, please browse our video page or this link.

​​        

Using high CRI and dimmable LED MR16 (aka GU5.3) bulbs for Halogen replacement is a good energy saving practice (besides the electrical power saving, ignited Halogen bulbs are very hot!). As it is supposedly a straightforward replacement, Electricians seldom pay attention to the 12Vac transformers that are required to be connected to the wall dimmer and the MR16 bulbs. Note the dimming function is realized by the wall (phase) dimmer and the dimmable LED MR16 bulbs; the function of a 12Vac transformer merely provides a stable power source for the light bulbs. First-thing-first, the electrician should always double-check if that’s a dimmable LED MR16 bulb being installed; of course, it would be difficult to understand about the product's dimming performance from the product package. 

  ​

• Look for “Dimmable” marking on product or package; if such logo / marking not found, it's assumed to be a non-dimmable product.

To generate the 12Vac, the traditional approach is to use the Iron Core transformer (MLV Tx), which tends to be very heavy and bulky. An Iron Core transformer consists of two coils to provide a step-down function from line voltage (primary side) to 12Vac (secondary side). While it’s rare to use MLV for new installation now, MLV may be encountered in retrofit applications and should not be a surprise to the Electricians.

Operating by completely different principle, the obvious advantage of the Electronic transformer (ELV Tx) is the size and weight compared to the MLV (not necessarily cheaper). ELV has some oscillating circuitry inside the transformer to provide a high switching frequency waveform in a 12Vac envelope, which is very different than that of the MLV. ELV is originally designed for Halogen bulbs (resistive load), which are required to provide enough current to keep the internal oscillation going. But depending on how the LED driver is designed inside the light bulb, some LED MR16 bulbs don’t draw enough current from the ELV Tx, which leads to unstable operation of the electronic transformer. 

• A 30W ELV transformer (front) and an 180VA (volt-ampere) MLV transformer (back)

“Backward compatibility” refers to the LED MR16 bulbs’ compatibility with the 12Vac ELV transformers. Poor backward compatibility issue typically manifests itself in the following phenomenon: (a) LED bulb flashing before any dimming operation or as soon as it is powered-up, (b) Stable lighting operation after dimmed down to a certain level. See video on the difference with LED MR16 bulbs dimming using MLV Tx and ELV Tx. In the video, the flickering at the bottom brightness level of the local brand LED MR16 bulb is more related to the LED driver IC inside the bulb and should be considered as a separate issue. To improve the backward compatibility, the advanced LED MR16 bulbs have “tricks” to simulate the current profile of Halogen load for the LED bulbs.

As shown in the video, a “wide backward compatible” bulb would provide consistent dimming performance with different types of transformers or ideally with different brands. Since there is little the Electrician can do in the field if only found such issue at installation stage, the advice is to spend on good backward compatible LED MR16 bulbs instead of trying to change different transformers at the site. To be safe, it won’t hurt to ask the product supplier in advance for recommended ELV transformers for a given light bulb before installation. 

Last but not least, while it’s common for many retailers to recommend using Incandescent (TRIAC) dimmers with the dimmable LED MR16 bulbs. We’d remind the Electricians that although it works for the demonstration, the leading-edge phase-cut would continuously cause current spikes and damage the dimmer in actual usage (proven), which the electricians need to be aware when they encounter some mysterious flickering or premature product burnt-out after operating for a while. In this job reference case, since the wiring in the ceiling had been done, we could only use a single DZ2G450DIAL in the restaurant kitchen to dim the OSRAM ET-LED 30 (12Vac electronic transformer) and a 7W narrow beam angle LED MR16 bulbs via the live wire (8 sets in total). The replacement is indeed very straightforward and costs much less if end-customer used the right products in the first place!

Below pictures show the original LED light and driver burnt-out during field visit.

 

DC 1-10V dimming is a common approach in a large area or high power consumption requirement LED strip light dimming application. Today’s market norm for LED strip application is to have around 14.4W/Meter and it’s common to have 10 meters long LED strip for the various indirect lighting purpose. Therefore, the power consumption required for the LED strip alone may easily be in the range of 150W - 800W per driver or 3000W+ for a large indoor area. Assuming only 80 lumen per watt, that's equivalent to 240000 lumen for the indoor area! Hence, dimming becomes a real energy saving practice to save the huge amount of energy consumption on indirect lighting.

• Lighting Design Remark: The biggest drawback of Indirect Lighting is about Energy Inefficiency. Huge amount of energy wastage on Indirect Lighting can defect the fundamental benefit of Energy Saving of LED Lighting!

Since a single 1-10V control can connect multiple LED drivers in parallel, DC 1-10V dimming gives flexibility to the installers and lighting suppliers for meeting the power requirements at different locations. In the implementation stage, there are different types of DC 1-10V dimming connection to be considered. Below left shows a setup that has a Standard Power Supply (12/24V) to provide the AC/DC function to the LED dimmable driver; below right shows a close look at this type of LED dimmable drivers available in the market.
 

Each Constant Current LED driver has a specific Output Voltage (V_OUT) range for the rated Constant Current output. For Non-Dimming applications, matching a LED Driver with a lighting fixture is mostly about selecting a LED driver that has the V_OUT range to cover the Forward Voltage Required to support the Target Constant Current Output operation (V_F @ Rated I_F).  Note that during the Dimming operation, the Phase Dimmable driver output current and output voltage will both be reduced continuously. 

Since LEDs from different LED chip suppliers have different I/V characteristic, some LED chips would have a wide Forward Voltage (V_F) range. Therefore, it’s likely that during the dimming operation with some LEDs, the driver V_OUT will be dropped outside its specified Constant Current Output Voltage range (V_OUT,MIN). 

To achieve Deep Dimming effect, detail understanding of both the Dimmable LED Driver Output and the LED Forward Voltage Ranges would be required, which makes Dimmable Driver selection little more complicated than that for Non-Dimmable Driver. As we try to show in our "LED Dimmable Driver Selection" Application Notes (see the bottom of this section), it would be wise to make proper measurements of an unfamiliar LED lighting fixture before matching it with the right LED dimmable driver.

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As our example below, let's say that we'd like to replace a Non-Dimmable LED Driver by a Phase Dimmable LED Driver so that a Downlight can achieve Deep Dimming effect.

Referring to the 300mA constant current output found in the non-dimmable driver description as our starting point, we set up the Programmable Power Supply to learn about the Operating Condition for a Downlight.

(Below Left) The Non-Dimmable LED Driver that originally comes with the Downlight.
(Below Right) Current Clamp Meter shows a Constant Current of 250mA from the Non-Dim LED Driver.

 

(Below Left) The operating condition for the 11.5W Downlight is V_F = 38.2V @ 300mA.
(Below Right) To Deep-Dim the Downlight, it is necessary to find out voltage at which it is barely on, which is V_F = 30.2V @ 1mA.

 

Once we’re clear on the Downlight's V_F range, we can easily use the 18W Phase Dimmable Selectable Constant Current LED Driver (MP_18W/350mA) and configure it at either 250 / 300 / 350mA output to suit for a particular application. Once the LED Dimmable Driver and the LED Lighting Fixture matching is done, we can use the right LED dimmer to achieve Deep Dimming performance.

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In general, we found that it would be easier to understand the Dimmable Driver selection by mapping the Driver Output Voltage ranges with the LED Forward Voltage ranges as illustrated below.  


To facilitate the Dimmable Driver selection discussion, we’ve created an Application Note to share our experience with the Lighting Professional, Electricians, or any interested parties. Please see our Application Notes (also available on the Support page for Download) and Video for details.  

While Two-Way Dimming is a common requirement in Lighting Application, having more than one dimmer in the line is forbidden in the traditional wiring approach. As a result, the implementation based on single pole dimmers would only allow dimming at a single location. Therefore, the resultant connection is actually a Two-way Switching-plus-One-Way Dimming, similarly for the Three-Way setup. 

As lighting control technology evolves, one way of solving this is to use Smart Dimmers. With Smart Dimmers, more than one dimmers can be connected wirelessly and paired to control the same light. However, as the Smart Dimmers must have its own electricity supply at all times, it’s common to see that such dimmers would require a Neutral Wire in order to be functional. Again, this may not suit for the Retrofit installation, where no Neutral Wire is available. 

Another approach to solving the unfulfilled market demand of True Two-Way Dimming is to develop an Upgraded Single Pole Dimmer that allows inter-communication among the dimmers, which in turn makes Two-Way Dimming-plus-Two-Way Switching operation possible. This is the target application of our Digital Multi-Way LED Phase Dimmers, DZ4G450MULT.

While our dimmer can be used independently, more than one dimmers can be connected together to form a proprietary network that controls the same lights from multiple locations, as if only a single dimmer was installed.

Unlike our previous offers, our DZ4G450MULT has three terminals: Terminal 1 for LIVE, Terminal 2 for DATA & Terminal 3 for DIMMED LIVE. When in Multi-Way operation, the MASTER unit is the one that connects to the light load and the rest of the units in the loop are the INTERFACE units that only have the LIVE (Terminal  1) and DATA (Terminal 2) connected back to the MASTER unit.

When more than one INTERFACE units are present, all the units should be connected to the DATA port of the MASTER unit. In other words, for the DATA port connection among the MASTER and INTERFACE units, it would be a PARALLEL connection for all the units in the loop. For convenient wiring, each DZ4G450MULT can be connected to the MASTER unit that is nearest to the lighting connection. 

See Product Video here.