LED Light Latest Protection Technology

First, why should the LED protect the white light LED, because there are many advantages, and more and more people enter people's daily life, its usage now becomes very huge. It is a new device, which has its own characteristics. White light LED is a voltage sensitive device. Do not exceed 20mA every LED lamp bead when working, and it will be easily burned if it exceeds too many LED lamp beads. If LED lamp beads are used normally, their life span is very long. But in actual use, LED lamp beads are often easy to break. What is the reason? In fact, the characteristics of LED lamp beads are not considered and the protection circuit is added to it. LED lamp beads are photoelectric semiconductor devices, which are easily injured by electrostatic during the assembly process. This requires static electricity protection during the assembly process. We found that many manufacturers do not have this concept or do not understand at all. LED lamp beads are based on a 20mA current in actual work, but often increase the current due to various reasons in use. If there is no protection measures, this increased current exceeds a certain time and amplitude. Later LED lamp beads will be damaged. Second, cause damage to LED lamp beads 1. Sudden increase in power supply voltage increase. There are many reasons for the sudden increase in the voltage of power supply power, such as the quality problem of the power supply, or the use of the user's improper use, etc. 2. A local short -circuit of LED power supply channels in a certain component or printed line or other wires in the line, which increases the voltage of this place. 3. A short circuit formed by the damage of a certain LED due to its own quality. Its original voltage drop is passed on to other LEDs. 4. The temperature in the lamp is too high to make the characteristics of the LED bad. 5. The water inside the lamp, the water is conductive. 6. During the assembly, I did not do a good job of anti -static work, so that the interior of the LED had been harmed by static electricity. Although the normal voltage and current value is applied, it is also easy to cause LED damage. These reasons will cause a significant increase in LED current, and soon the LED chip will be burned due to overheating. According to our experience, most of the LEDs are bipolar short circuits, and a small part is a disconnection. Each LED has a pressure drop of about 3.2V. If it is burned, it will not shine if the disconnection is broken. If this voltage is short -circuited, it is transferred to other LEDs, causing a larger current of other LEDs, and other LEDs will be burned faster or even critical of power supply. Originally, it was very easy to cause major accidents. LED is generally installed at a high place, it is not easy to install, it is even more difficult to repair. Therefore, the protection of LED is a actual demand, but it is not valued by everyone at present. It is also a problem that many people have no choice but to deal with it. Third, how to protect the LED for the protection of the LED, we first think of the insurance tube, but the insurance tube is one -time, and the response speed is too slow. It is used in the products of LED lights now, because LED lights are now mainly in the city's glorious project and lighting project. In response to this practical needs, we did a lot of experiments and summarized the characteristics of the LED protection circuit according to the requirements of the project. It was disconnected, so that the LED and the power supply can be protected. After the entire light is normal, it can automatically restore power supply. It does not affect LED work. The key is because it is a civil product. Cost with low cost. These requirements are contradictory and restrict each other, and it is difficult to achieve. First of all, it should be determined which protection circuit and protection device to choose. 1. We can choose to use transient voltage to suppress the diode (referred to as TVS). Inspector voltage suppressing diode is a high -efficiency capable device in the form of diode. When its pole is impacted by reverse transient high -energy, it can immediately reduce the high resistance between the poles to low resistance at a short time of 10 seconds in a short time of 10. , Clating the voltage between the two poles in a predetermined voltage value, effectively protects the precision meta components in the electronic line. The transient voltage suppress the diode with fast response time, large transient power, low leakage current, good breakdown voltage bias consistency, more controllable clamp voltage control, no damage limit, small volume and other advantages, etc. But in actual use, I found that it is not ideal. First of all, it is not easy to find TVS devices that meet the voltage value. The TVS device is mainly used in lightning protection and lightning protection, and overvoltage absorption above 220V, while the power supply voltage of LED lights is generally 24V or 12V. This voltage value has very few tvs products, and the test is not good. At the same time, we know that the damage of LED lamp beads is mainly caused by the overheating inside the ambassador chip of the current. TVS can only detect over -voltage and cannot detect the current. Overvoltage is definitely the cause of over -current, but it is difficult to master the appropriate voltage protection point. It is difficult to use this device or it is difficult to use in actual. 2. We can choose to recover the insurance tube. Self -recovery insurance tube, also known as polymer polymer positive temperature thermistor PTC, is composed of polymers and conductive particles. After special processing, the conductive particles form a chain -shaped conductive channel in the polymer. When the normal operating current passes (or the component is at normal ambient temperature), the PTC self -recovery fuse is in a low resistance state; when there is an abnormal current in the circuit (or the ambient temperature rises), the large current (or the environmental temperature increases) The heat generated quickly expands the polymer, and the conductive channels composed of conductive particles are cut off. The PTC self -recovery fuse is high -resistance; when the current (over -temperature state) in the circuit disappears, the polymer is cooled, the volume recovery Normally, the conductive particles re -constitute the conductive channel, and the PTC self -recovery fuse is initially low -resistant state. In normal working state, the fever of the insurance tube is very small. In the abnormal working state, the heat is very high. It is limited to the current through its current, which plays a protective role. Its size, low cost, can be used repeatedly, realizing the automatic start of protection and automatic exit; it is a solid -state packaging impact to be damaged easily; we found in the actual test: Since it is a thermal sensitive device, it is subject to temperature. The impact is very large. Since the PTC is encapsulated inside the lamp, the light beads must be fever and it will affect the work performance of the PTC. For the determined lamps, you can choose the PTC through the test. The more reliable method is to keep it away from the heating lamp bead. In the specific circuit, there are two ways to choose from: 1. Generally, LED lights are divided into many string of connection roads. For example, 24V voltage, we all use 7 LED lamp beads to connect in series and add a resistor. The current is generally 17 19mA. As needed, we can choose 7 integer light beads to combine into a whole lamp. We can add a PTC component in front of each branch to protect. The advantage of this method is that the accuracy is high, and the reliability of protection is good. 2. Overall protection. Add a PTC component in front of all light beads to protect the whole light. The advantage of this method is simple, not occupying the volume. We generally choose this method. As far as household products are concerned, the result of this protection in actual use is still satisfactory. The choice of PTC is very particular. We all explored the more accurate corresponding value through a long time of experiments. Fourth, the LED's electrostatic protection all the substances are composed of atoms, and the atoms have electronics and protons. When the material is obtained or lost electrons, it will become negative or positive electricity. These charges accumulate on the surface of the material and we call the object with static electricity. The accumulation of charge is usually caused by the separation of the materials and the mutual contact, or it can also be caused by friction. It is called friction. There are many factors that affect the accumulation of charge, including contact pressure, friction coefficient and separation speed, etc. The electrostatic charge will continue to accumulate. If there is no leakage channel, this value will eventually reach very high until the effect of the charge generated by the charge is stopped, the charge is discharged or reached enough intensity, it can penetrate the surrounding material medium as the medium of the surrounding material. After the electronics is broken, the electrostatic charge will be balanced quickly. The rapid neutralization of this charge is called static discharge. Because the voltage is quickly discharged on a small resistance, the current will be very large, which may exceed 20 ampel. If this discharge is performed by static electrostatic elements, such a large current will be designed to be designed to be only 3V and more than 3V and more and more. The current is 20mA LED caused serious damage. 1. Why should the protection awareness of static electricity be improved before the previous generation of this century 70, many static electricity problems were caused by people without a sense of electrostatic protection. Even now many people suspect that static discharge will cause damage to electronic products to damage electronic products. This is because most electrostatic discharge damage occurs below the human feeling, because the human body's perceived voltage of static discharge is about 3KV, and many electronic components will be damaged when they are hundreds of volts or even dozens of volts. Usually electronic devices are discharged by electrostatic discharge discharge. There is no obvious boundary after damage. After installing the components on the device, there are many problems. The analysis is quite difficult. Especially for potential damage, it is difficult to measure the performance of its performance even with precision instruments. However, the experiments have confirmed in recent years that this potential damage has decreased significantly after a certain period of time, and the reliability of electronic products has decreased significantly. The damage caused by electrostatic is definitely true. 2. What are the forms of static electricity damage to electronic products? The basic physical characteristics of static electricity are: attracting or exclusion, there is a difference in potential difference with the earth, which will generate discharge current. These three characteristics have three effects on electronic components: Static electrostatic adsorption dust, reducing component insulation resistance (shortening life). Static discharge discharge damage so that the component cannot work (completely damaged). The heat generated by the electrostatic discharge field or the current, which hurts the component (potential damage). The situation is more common, and it is difficult to be discovered in time. 3. What are the characteristics of static electricity damage to electronic products? (1) The hidden human body cannot directly perceive static electricity unless static discharge occurs, but the human body may not have an electric shock. 2-3kv, so static electricity is hidden. (2) The performance of some electronic components after the electronic component is not significantly reduced after the electrostatic injury, but many accumulated discharge will cause internal injuries to the device and form a hidden danger. Therefore, static electricity is potential to damage the device. (3) The generation of random static electricity also has randomness. Its damage is also random. (4) The failure analysis of complex electrostatic discharge damage, because of the fine, fine, tiny structural characteristics of electronic products, it takes time, time, and expensive. Even so, some static damage is difficult to distinguish from damage caused by other reasons, so that people can mistake the static damage as other failures. Before the damage to static discharge was fully understood, it was often attributed to the early failure or unknown failure, which unconsciously covered the real cause of the failure. Therefore, the analysis of electrostatic damage has complexity. 4. How to control static discharge? From the previous analysis, it can be seen that static electricity is generated by the separation of object contact, and even induction that is not touched. It is almost impossible to completely eliminate static electricity, but some measures can be taken to control the static electricity does not cause harm. 5. How to control human static electricity (human static protection)? The human body is the most common source of static electricity hazards. For static electricity, the human body is a conductor, so it can take ground measures to the human body. (1). Use anti -static ground/anti -static shoes/socks (static electricity guide from the foot to the earth) through the feet to wear anti -static ground, floor mats, carpet, personnel put on anti -static shoes socks to form a combined ground ground. (2). Wear anti -static wristbands and ground (static electricity guide from hand to the earth) uses hand to leak the body's static electricity. It consists of anti -static and loose band, activity button, spring soft line. Protect the resistance and plug or chip composition. The inner layer of the loose band is woven with anti -static yarn, and the outer layer is woven with ordinary yarn. 6. In the use of anti -static shoes and wristbands, the problem of human safety in the use of wristbands is only considering from the perspective of anti -static, the smaller the total ground resistance of the human body, but the minimum value is limited by security. Resistance, in case the resistance can limit the current of the human body in the case of a short connection between metal devices or devices or power frequency power supply. The minimum value should not be less than 105ω, The maximum does not exceed 109ω. 7. What problems should I pay attention to in the use of anti -static shoes and wristbands? Do not disconnect when using wristband operations, otherwise it will lose grounding effect. The main problem of the use of various wristbands is to open the way, sometimes temporary, sometimes disconnected for a long time, making the loss of grounding. , the wristband is not deducted, causing the contact resistance of the human skin and the wristband, and the resistance of some wristbands is the strap itself. When the belt touches the ground danger. 无, some claim to be a wireless wristband, the effect is far less effective than that of wired. 在, anti -static shoes should have anti -static socks/insoles when worn, and work on the anti -static ground can make the static electricity brought to the earth by the human body. Excessive or disconnection of any part of the human body will cause the human body to bring the harmful static electrostatic electrostatic. Therefore, in important departments, there should be a human resistance tester to detect the shoes/socks/insoles worn by the human body at any time and whether the total resistance of the human body can have the requirements for leaking static electricity. The ground wire of the 的 wristband application is connected to the ground with the ground line and cannot be sandwiched on the metal body on the desktop or table, because the resistance of these metal body on the ground may be very large. 腕Che frequently check the resistance of the wristband 5. The anti -static product and other appliances used in the electrostatic protection workshop working area of the LED production workshop. After a period of time, the resistance may be greater than 109. In order to achieve the purpose of anti -static, it is recommended that, the main suggestions, the main main suggestions, the main maintenance, the main mainly Create the basic conditions of the following four aspects. One is to ensure the implementation of human protection measures; the other is to ensure the electrostatic protection of the production equipment of the workshop; the third is to strive to make the production workshop and the surrounding environment of the anti -static electricity; the fourth is to improve the system and formulate operation specifications , Establish a strict internal examination and inspection system to ensure that the system is implemented and pay attention to the training of electrostatic consciousness of employees; formulate technical standards for electrostatic protective products to ensure the quality of protective supplies. In terms of measurement and control methods, add temperature and humidity monitoring to the work area, record the temperature and humidity daily; measure the static voltage every month; the employee anti -static clothing, the hat every time the surface resistance and friction voltage are detected One surface resistance. Set the comprehensive resistance value tester at the door of the workshop; the balanced voltage and electrostatic dissipation time of the ionic fan once a month. During the production process, please pay attention to taking appropriate prevention measures. The following is for reference only: It is necessary to prevent static electricity: wearing anti -static clothing (such as anti -static clothing, hats, shoes, fingers or gloves, etc.) during operation Electric electricity dispersing on the surface or inside: The assembly operator needs to wear anti -static wristbands. (The wristband must be connected to the grounding system.) It can provide a shielding protection and protection of the sudden discharge of static electricity or the impact of the electric field: The assembly table (workbench) needs to be used to use the anti -static radio. Install LED need to use anti -static component box. The soldering iron, foot cutting machine, tin furnace (or automatic return welding equipment) must be grounded. During the operation, avoid touching the tube of the luminous pipe directly as much as possible, and touch the colloidal part as much as possible when it is taken. The grounding measures should be completely prevented from the production of static electricity. The grounds of the workbench, soldering iron, foot cutting machine, and tin furnace (or automatic backwaller equipment) must be introduced in the soil with thick iron wires. , Buried in the surface below 1 meter, all ground lines need to be connected to the main line. If the static ring that the operator is worn has a line, it will also need to lead the line to connect to the buried line. Half -finished products and finished product testing equipment also need to be grounded.