Three common failures of LED signal lights and solutions

Some friends ask the common reasons and treatment methods of LED signal lights flashing, and some people want to ask the reason why the LED signal lights do not light. What’s going on? In fact, there are three common failures and solutions to signal lights.

Three common failures of LED signal lights and solutions:

A common fault is rectifier failure. Go to light City and buy one and replace it. The entire led is rarely damaged.

Two. Led signal light flashing reasons:

1. The lamp beads and led drive power does not match, the normal single 1W lamp beads bear :280-300 ma current and :3.0-3.4V voltage, if the lamp chip does not have enough power, will cause the light source stasming phenomenon, if the current is too large, the lamp beads will not be able to withstand the switch. In severe cases, the gold or copper wires inside the beads can burn out, causing the beads to fail to work.

2. The drive power supply may be damaged, as long as you replace it with another good drive power supply, it will not blink.

3. If the driver has the function of overtemperature protection, the heat dissipation performance of THE LED signal lamp cannot meet the requirements, and the overtemperature protection of the driver will blink when it starts to work. For example, the 20 w projection lamp housing used to assemble 30W lamps does not do a good job of cooling.

4. If outdoor lamps also have stroboscopic phenomena, it means that the lamps are flooded. As a result, if it blinks, it doesn’t light. The beacon and the driver are broken. If the driver does a good job of waterproofing, the lamp bead is broken and the light source can be changed.

Three. Processing of led signal light flashing method:

1. In off-line low-power LED lighting applications, the common power topology is the isolated flyback topology. The Green Dot, an 8W off-line LED driver, meets energy Star solid-state lighting standards. In the design case, because the sinusoidal square wave power conversion of the flyback regulator does not provide constant energy for the primary bias, the dynamic self-powered circuit may activate and cause light flicker. To avoid this problem, it is necessary to make the primary off-set discharge in each half cycle. Therefore, it is necessary to properly select the capacitance and resistance values of the LED signal lamps that constitute the circuit.

2. Normally the human eye can perceive the flicker of light at a frequency of 70 Hz, but above that it cannot. Therefore, in led lighting applications, if the pulse signal has a low frequency component with a frequency below 70 Hz, the human eye will feel a flicker. Of course, there are many factors that can cause LED lights to blink in a particular application.

3. Emi filters are required even in led drive applications that provide good power factor correction and support dimming of three-terminal bi-directional SCR switches. The transient current induced by the step of the triterminal bidirectional SCR switch excites the natural resonance of inductors and capacitors in the emi filter.

If the resonance characteristic causes the input current to be lower than the hold current of the three-terminal bi-directional SCR switch element, the three-terminal bi-directional SCR switch element will be turned off. After a short delay, the three-terminal bidirectional SCR switching element will usually turn on again to excite the same resonance. This series of events may be repeated many times within a half cycle of the INPUT power waveform of the LED semaphore, resulting in visible LED flickering.