Flickering is one of the most common problems with LED strips. By reading this article, you will learn the types of flickering, the causes of flickering, and how to fix flickering.
What Are the Different Types of Flickering?
Flicker is a quick on/off cycle of a light source. It can be intentional (nightclub or concert flashing), but usually, it’s just a nuisance.
There are two types of flicker: visible and invisible. Visible flicker is anything with a frequency below 100 Hz (i.e., 100 times per second or less). Invisible flicker occurs above 100 Hz and is invisible to our eyes when it is present. Both types of flicker are unhealthy–common disorders include dizziness, eyestrain, headaches, migraines, and cognitive impairment. Visible flicker can also induce seizures in individuals with epilepsy.
What Are The Causes Of LED Strip Light Flickering?
Here are some common causes of LED strip flickers.
Visible Flicker Causes
Flicker starts (or gets significantly worse) after connection. The main reason is that poor, inconsistent, or intermittent connections may cause flicker by alternately making and breaking circuits. It occurs primarily in solderless connectors and is unlikely to occur in soldering.
The LED strip flicker will change or disappear when you press the solder-free connector.
This usually happens when the LED strip is dimmable. First, you must ensure that your LED strip and driver are supported for dimming. Then, you need to ensure that the dimmer and driver protocols are compatible. For example, you can’t use a 0-10V dimmer with a DALI dimming driver.
Overloaded or Defective Power Supply
LED driver overload is one of the most common causes of LED strip flicker.
LED drivers usually have overload protection. When overloaded, the LED driver will be constantly on and off. Then the LED strip will also be constantly on and off, so it seems to be flickering.
A defective LED driver can, at some times, also cause the LED strip to flicker.
Defective LED Strip
The LED strip sometimes flickers because the LED strip is defective.
In most cases, it is a bad connection between the LED chip and the holder.
In the picture below again, you can see the internal structure of the SMD LED beads. The part that emits light is the LED chip, and the LED chip is connected to the LED holder by a gold wire. When the LED chip and the bracket are not connected well, the current can sometimes pass through and sometimes not, and the LED will flicker.
Compared to SMD LEDs, CSP and COB LEDs do not have gold wires and can avoid this problem. For more information, please read the CSP LED Strip VS COB LED Strip.
There is also a situation where the LED beads and PCBs are not well soldered. When you find a specific part of the LED strip blinking, you press this part of the LED with your hand. The flicker may change or disappear.
Invisible Flicker Causes
Perhaps you see some vertical lines in your smartphone’s camera photos and observe some strobe in moving objects, a phenomenon caused by the invisible strobe.
AC Power LED Strip
Electric lights flicker because most of the world’s electricity is transmitted via alternating current (AC). As its name implies, AC changes its direction ーー flows in one direction and then turns at a rate of 50 to 60 times per second. This usually takes the form of a sine wave. However, direct current (DC) is constant and always flows in one direction.
When the current flows in the opposite direction, anything plugged into the line loses power instantly. Because the current constantly flows in the opposite direction, all the lights will flicker.
This is also the reason why the AC power LED strip is flickering.
PWM signal dimming produces invisible flickers.
PWM is the intentional manipulation of DC power between the on and off states. By varying the relative time between its on and off conditions, PWM can be used to create the perception of different brightnesses. However, the LED is either 0% or 100% bright. To achieve the illusion of 50% brightness, the LED is half the time at 0% brightness (off) and half the time at 100% brightness (on).
This flicker does not usually pose a problem because it is not visible. However, for recording video, these invisible flickers would be a disaster.
The light flickering in a video becomes more evident and apparent because the camera’s frames per second (FPS) recording is not aligned with the frequency of electricity. This is known as the ‘strobe effect’.
Almost all LED strip dimmers and “color changing” controllers (CCT or RGB) installed on the low voltage DC side of the circuit use PWM to achieve their desired effect. Unfortunately, many PWM dimmers use frequencies that are too low. The frequency should be 25,000 Hz or higher to eliminate the impact of PWM flicker. Still, most PWM dimmers do not include a PWM frequency specification, which usually indicates that they use a frequency of a few hundred Hz at most.
For more information about LED strip dimming, please read How to Dim LED Strip Lights.
How To Stop LED Strip Lights from Flickering?
Referring to the following suggestions, we can avoid the LED strip flicker.
Inspect the Connection
First, we need to check all the connections, including wires, connectors, and LED drivers, to ensure the connections are good. Bad connections can make too much resistance, heat up badly, and possibly cause a fire. Of course, it will also cause the LED strip to flicker.
Replace Incompatible Parts
Second, I need to replace incompatible components such as dimmers, LED drivers, etc. The most likely incompatible parts are dimmers and LED drivers.
Replace the LED Driver
Replace the faulty LED power supply, or use a higher wattage power supply.
Please note that it is impossible to use multiple LED drivers to connect a single LED strip when the LED driver’s power is insufficient. Because of the inconsistent start-up time of LED drivers, the driver that starts first with insufficient power will cause overload protection, then shut down and restart again. Then all the drivers will keep starting and shutting down.
Replace Faulty LED Strips
Finally, you need to replace the faulty LED strip. When you make sure the connection is good, all parts are compatible, and the LED driver is okay, you finally have to replace the LED strip.
Use Low Voltage DC LED Strip Lights with LED Drivers
We use low-voltage LED strips and high-quality LED drivers whenever possible. LED drivers convert high-voltage AC into stable low-voltage, thus ensuring that the LED strips are flicker-free.
If you want to understand the famous LED driver brand quickly, you can read Top LED Driver Brand Manufacturer List.
Use Dimming Power Supplies with CCR Output Signal
The output dimming methods of dimming power supply are mainly divided into two types, Constant Current Reduction (CCR) and Pulse Width Modulation (PWM) (also known as Analog Dimming).
In CCR, the current flows continuously through the LED. So the LED is always ON, not like in PWM, where the LED is always turned ON and OFF. The brightness of the LED is then varied by changing the current level.
Use Dimming Power Supplies with High Frequency PWM Output Signal
In PWM, the LED is turned ON and OFF at its rated current at a high frequency. The rapid switching is high enough for the human eye to see. What determines the brightness level of the LED is the duty cycle or the ratio of the time when the LED is ON and the total time of one complete cycle.
The higher the camera will see the frequency of the PWM, the less likely the flicker. Frequently more than 25 kHz, the camera cannot see the flicker.
We must avoid LED strip flicker, including visible and invisible flicker.
After reading this article, you are an expert in LED strip flickering.
Please leave us a message below if you have any questions or problems.