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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.

Using 12V LED Strips to Explore Constant Voltage vs. Constant Current LED Dimmable Drivers

LED Strip Light has found its wide applications due to its flexibility in creating different size and shapes. While most of the LED Lighting Fixtures are driven by Constant Current LED drivers, LED Strips are commonly driven by Constant Voltage LED Drivers have also occupied a significant portion of LED Lighting Fixtures. Signage, Light Boxes or Cabinet Lighting are commonly built based on Constant Voltage LED strips. The same product idea can be applied to a much larger scale for Indirect Lighting in Building Lobby etc. 

With Proper Heat Dissipation in place, the LED strips would work fine in principle. If LED strips are required to be dimmed, it’s common to use 0/1-10V based dimming approach. From our project experience, our DZ1G1TEN and PWM-120-12/24/36/48 ​from Mean-Well combination have demonstrated a good product solution for large-scale applications. Since each controller can be easily used with multiple 0/1-10V dimmable drivers, the costs advantage of such dimming approach is obvious for simple applications


Recap of 0/1-10V Dimming Control Connections
Before we look into the new topics in this video, the following circuit diagram shows the Typical Connection of 0/1-10V Controllers with such type of Dimmable LED Drivers. The key difference is that for 1-10V Control, no additional AC wires are required; but for 0-10V Control, the controller must have its own AC Inputs in order to generate the 0V signal to the Dimmable LED Drivers. 


In fact, if no dimming is required, the LED strips can be connected directly to any standard LED driver or Power Supply Unit with the right Constant Voltage output. It’s very important to use the right output voltage to match with the strips since it has been reported wrongly applied the Drivers with Different Output Voltage (e.g. 24V Driver > 12V LED Strips) resulting in Fire!
 
  • Note Thermal Runaway can be a potential issue in practice. In the market, some low costs LED panels are built based on LED strips (same as Lightbox). It has been reported that after using these types of LED panels for some months, these panels would begin to show different types of problems.
  • A simple way to tell the LED configuration inside the panel is to check the output of the LED drivers: Either it is rated by Constant Current or Constant Voltage. Because of the different LED configuration inside the panel, a 600 x 600 LED panel that requires the Constant Current type of LED driver usually has a higher input voltage requirement, such as 60V / 700mA.
  • For 1-10V Dimmable LED Panel applications, our product recommendation is DZ1G1TEN +  LCM-25/40/60 from Mean Well.
  • For Phase Cut Dimmable LED Panel applications, our product recommendation is DZ4G450MULTPWM-40/60 from Mean-Well.


Can we Use Constant Current LED Drivers on LED Strips?
We've said that it's common to use Constant Voltage Dimmable Drivers for 12/24V LED Strips. But can we also dim a regular 12/24V LED strips by Constant Current type of LED Drivers? If so, what are the considerations for using Constant Current LED Drivers to dim LED strips? How do both types of Drivers dim perform differently? 


In this video, we explored these questions by dimming two reels of 12V LED Strips separately by both types of TRIAC Dimmable Drivers side-by-side comparison. As shown, both types of drivers can be used with 12V LED Strips, but with slightly different results (See 04:00 in this Video). 


Selecting LED Drivers for LED Strips - LED Strip Length Consideration
Selecting a Constant Voltage Dimmable LED Drivers for the LED strips is simple. As long as the Correct Output Voltage (i.e. Driver Output Voltage = LED Strip Rated Voltage) is used and the Driver’s  Rated Power is sufficient for LED Lighting Load, the same driver can be used without considering of How Long the strips Can Be Connected. This becomes a key consideration when we're not sure the exact length of the LED strips to be added in advance. In terms of connection, adding LED strips in parallel is much easier to do and it's a common wiring approach in Lighting. 


Although uncommon in practice, if we consider LED strips as just another LED Lighting Fixture, certainly we can also use the Constant Current type of drivers to dim the fixture. Same as we suggested in our LED Dimmable Driver Selection Application Notes, we can first measure the Corresponding Driving Voltage at the Desired Driving Current and determine the appropriate Constant Current Driver that can meet the Driving Condition.

Immediately we realize that matching a Constant Current LED Driver with a LED Strip implies that different lengths of the LED strips would require different Driving V/I Outputs. This means a different Constant Current Driver would be required. Hence, in this video, to make our demonstration easy, we used a Multi-Output (Multi-Power / Selectable Constant Current) LED Dimmable Driver to match the 12V LED Strips when we have more reels connected together. 

It’s then easy to see that for LED Strips kind of application, Constant Voltages LED Dimmable Drivers are definitely easier to use than Constant Current Drivers, but not necessarily better than Constant Current LED Dimmable Drivers.




Some Dimmable LED Drivers Terminologies 
When we talk about Dimmable Drivers, it’s common to hear the terms: Pulse Width Modulation (PWM) and Constant Current Reduction (CCR). These terms actually describe the dimming approach for the LED Dimmable Drivers. For Constant Voltage drivers, PWM is the way to change the Duty Cycle in order to adjust the power input to the Light. For Constant Current drivers, Constant Current Reduction is to reduce to actual current flowing into the Lights. This is the fundamental principle for dimming LEDs. Please refer to our Application Notes and other sections in Technology page for details. 
 
  • When we talk about Phase-Cut and 0/1-10V Dimming Control, do not confuse these terminologies with the PWM or CCR. Simply put, the Phase-Cut and 0/1-10V Dimming Control describe how the input would be changed to the Dimmable LED Drivers; they are about how the Dimmable Drivers are dimmed.
  • If we keep the Phase-Cut and 0/1-10V as the Input to the LED Dimmable Driver and the PWM and CCR as the Output of the LED Dimmable Driver, the concepts should be clearly distinguished. 


Comments on TRIAC Dimmable LED Constant Voltage Drivers
Since we’ve been marketing our dimmers, we came across many different TRIAC Dimmable Constant Voltage LED drivers in the market with varied quality. Almost all these drivers have identical product specification (Output Voltage & Rated Power), so from our experience of finding a compatible driver and can demonstrate good dimming performance with our Phase Dimmers, we notice some key points to consider: 

 
  • Many of these drivers exhibit Severe Inrush Current and or Repetitive Currents (esp. when the drivers get over 200W); this can create Electrical Stress on Digital LED Dimmers. 
  • Many of these Drivers Only Support Leading-edge Dimming and Do Not Respond to Trailing-edge Dimming