How to ensure that the LED switching power supply is protected from lightningTime:2021-04-12 / Read:374
LED switching power supply products are widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instrumentation, medical equipment, semiconductor refrigeration and heating, air purifiers, electronic refrigerators, liquid crystal displays, LED lamps, communication equipment, audio-visual products, security monitoring, LED light strips, computer cases, digital products and instruments and other fields.
How to ensure that the LED power supply is protected from lightning strikes? The lightning protection design of the switching power supply needs to meet the requirements of the lightning protection standard: EN 61000-4-5; the lightning protection requirements of different application ranges are also different. Choose the input discharge tube, PTC resettable fuse, and varistor specifications according to the needs. The larger the size, the better the lightning protection effect of the component itself, but when the specifications are too large, the internal components of the power supply cannot be protected well, so when choosing the model of the switching power supply lightning protection component, the protection level of the product must be combined And the scope of application.
Varistors and gas discharge tubes are commonly used lightning protection components in switching power supplies.
The single-phase parallel anti-lightning surge circuit based on varistor and ceramic gas discharge tube is applied to the switching power supply of the instrument. The whole circuit includes a lightning protection circuit and a switching power supply circuit. The lightning protection circuit uses 3 varistors and a ceramic gas discharge tube to form a composite symmetrical circuit, which is fully protected by common mode and differential mode. It composes the power circuit of the lightning protection instrument with the classic switching power supply circuit. The varistor is used in parallel to extend the service life. After the varistor fails in short circuit, it will be separated from the switching power supply circuit and will not cause fire. In the lightning protection of switching power supplies, gas discharge tubes are often used as primary protection, and the rear end is connected in series with a varistor to discharge residual pressure.