It is very suitable for overcurrent and thermal protection of LED lighting systems. Conclusion PPTC has many characteristics. In terms of design, PTC devices can be placed on metal core circuit boards or LED heat sinks to achieve optimal heat conduction, making PPTC repairs more real-time and effective. In addition, PPTC products have various packaging forms, which can be customized according to customer requirements, with high flexibility. But there is no standard solution for overheating maintenance, and the specific design must be combined with the actual luminaire and fully verified.

When high-power white LEDs are used as new green lighting, <when high-power white LEDs are used as new green lighting. It will have advantages such as high light conversion efficiency, low power consumption, long life, and no maintenance, so it will gradually be used in various lighting fields. LED long life is based on its safe working environment. For LED lighting, there are two main threats that affect its life; one is over-electric shock, where the over-electric shock is that the current applied to the high pole lamp exceeds the maximum rated current in the LED technical data sheet, including over Overcurrent impact caused by voltage; the other is overheating damage. These damages can manifest as immediate failure of components, or they can occur long after an electrical shock event, shortening the LED operating life.

The second is the failure of the LED components themselves. Usually, the damage to the LED power supply and driver comes from the over-electric shock of the input power supply (EOS) and the open-circuit fault of the load terminal. The over-electric shock of the input power supply often causes damage to the driver chip in the driver circuit and breakdown damage to active components such as capacitors; The short-circuit fault at the load end may cause the overcurrent drive of the drive circuit. The reason for the damage of the LED lamp is the failure of the power supply and the drive. The drive circuit may be damaged by short-circuit or overheating caused by short-circuit fault.

Refers to the situation that the current flowing through the LED exceeds the maximum rated current in the technical data sheet of the LED street light, and the LED component itself fails. Transient over-current events Transient over-current events. This may be due to the direct occurrence of high current, or it may be due to the indirect occurrence of high voltage, such as transient lightning strike, transient switching noise of switching power supply, overcurrent caused by overvoltage events such as grid shaking. These events are transients with very short duration, usually I refer to them as spikes, such as "current spikes" voltage spikes". Transient overcurrent events also include when the LED is powered on or hot plugged in. Transient overcurrent.

ISO7637-2 transient load dump surge, for LED lighting in automobiles. It is an important threat to its normal operation. The failure mode of an LED after an over-shock is not fixed, but it usually results in damage to the solder wire, as shown in Figure 1. This damage is usually caused by extremely large transient overcurrents, which, in addition to blowing the weld wire, can cause other localized damage close to the weld wire, such as sealing materials.

One of the most common transient overvoltage hazards in transportation and applications, electrostatic discharge events ESD damage is currently a highly integrated semiconductor component manufacturing. The LED lighting system needs to meet the IEC61000-4-2 specification of human body electrostatic discharge mode "8KV contact discharge" to prevent the system from over-electric shock failure that may be caused by electrostatic discharge.

As shown in Figure 2, the performance of the LED PN junction array is degraded or damaged. The internal failure of the LED street light chip caused by the discharge path of the ESD event may only cause partial functional damage, and in severe cases, the LED will be permanently damaged.