Besides energy saving, controllability is the next highly expected feature of LED Lighting over Traditional Lighting. However, such a control aspect seems to be missing in daily applications. Since 2015, we've been developing & marketing Phase Dimmers* and related products to address LED dimming control

Driven by our project field experience, we developed a new type of Tunable White control using Phase Dimming & 0-10V technologies, which gives our Tunable White Controller (DZ1G300TUNE) & Dynamic Lighting Controllers (DZ2G300TUNE_TOGG / _PUSH). It's our goal to lower the technical and costs barriers for different Circadian Lighting or Commercial applications that desire Multi-Purpose Lighting.

* Our 450W / 220-240Vac Single Live-wire Operational Trailing-edge LED Phase Dimmers released to market includes DZ2G450DIAL & DZ1G450CAPS (2015), DZ3G450DIAL (2017), DZ4G450MULT (2018). In 2017, our DZ3G450DIAL was listed as a SORAA® Compatible dimmer. In Q2 2021, an Enhanced version of DZ3G450DIAL has been available.

In this Application Video Library, we shared a number of interesting topics on LED dimming or how our products can be applied in different scenarios.

How to Select Dimmable LED Driver to Match a COB Light and Achieve Deep Dimming Effect?

In today’s market, Standard LED Dimmable Lamps (MR16, GU10, E27, E14, …) and COB Downlights represent two types of mainstream LED Lighting products. COB Downlight is a typical application of LED Lighting: The Downlight only consists of a light source (LED in COB package), heatsink and mounting clips.

The LED Driver is externally connected and it’s up to Lighting Supplier / Lighting Designer / Electricians to select the appropriate LED drivers for the light, Dimmable or Non-Dimmable. While the Non-Dimmable Constant Current LED Driver selection is straight-forward, selecting Dimmable LED Drivers for a particular LED Light & having it to deliver Deep Dimming effect is more complicated.

First of all, depending on the application, different types of Dimming Control methodology can be selected, such as DALI, 1-10V or Phase-Cut Dimming Control. With advanced COBs that allow Correlated Colour Temperature (CCT) to be changed directly using LED Dimmers, "Dimmable Downlight" expands its application from Simple Brightness Control to Human Centric Lighting, which implies getting Warm White / Neutral White / Cool White out of the Same Lighting Fixture. 
This video is a complementary material to our LED Dimmable Driver Selection Application Notes, in which we explore how to select LED Phase Dimmable Drivers to match-up with a COB Downlight. In particular, we want to focus on how should the LED Driver Output Voltage Range map with the LED Downlight Forward Voltage Range in order to give the desired effects. In our Application Notes, we also covered various problems when we simply used the provided information on product stickers for the selection criteria.

From our Application Notes, we mentioned that: 


  • In order to deliver the desired results, a proper understanding of the proposed LED Dimmable Drivers and the Forward Voltage (VF) / Forward Current (IF) Characteristics of the Downlight on-hand would be the Key-to-Success here. As the Driver Output Voltage (and hence, the Driving Current to the Downlight) will continue to drop as we Dim, we shall consider the Rated Constant Current of a Phase Dimmable Driver as the Maximum Driving Current to the Downlight.


  • The second point to consider is to understand the LED's entire Forward Voltage Range for it to achieve Dim-to-Off or the Desired Dimming / CCT Level. In the case of Dim-to-Warm application, if the Dimmer-Driver combination is not capable of driving the LED deep enough, the Downlight would not give the Amber color desired, even if the Datasheet says otherwise.

Measurements Are Importance!
Unfortunately, these kinds of information are usually not available on the Downlight Datasheet. Unlike using Trial-&-Error approach, this is the part where Measurements should be taken in order to identify the appropriate Dimmable Driver for the job. In our Application Notes, we’ve summarized different measurements to be made, such as VF, MIN, VF @ Target Operating Current, VOUT Ranges, VOUT, MIN and VOUT, CUT-OFF.

When more than a Single Driver is being considered,  we suggested using a Graphical Approach (similar to below) for easy identification of how the Driver Outputs and the LED Forward Voltages are matched. In practice, when we only have access to a Limited Dimmable Driver Portfolio, the various trade-off must be considered, such as Delivering the Lower End of the Light Spectrum vs. Not Driving the Light @ Maximum Brightness.

In this video, we picked up some Downlights randomly from our Retail Partners and either replaced the original Non-Dimmable Driver or just selected a Dimmable Driver to match the COB Downlight. When facing an unfamiliar Lighting Fixture, our Application Notes emphasizes the importance of making the measurements of the relevant parameters before product selection.
In this video, we used the HEP TRIAC Dimmable 6W / 350mA (LMTC6W350-Z), 15W / 350mA (LMTC15W350-Z) and the 18W Selectable Constant Current LED Drivers to match with the different Downlights. 

For further reading, we encourage interested parties to browse our Application Notes to better understand the background of this exercise and other issues we encountered or taking a peek or a Quick Summary in our Technology / Phase Dimmable Constant Current LED Driver Selection section.