High power LED provides incandescent or CFL lamps is unable to provide long working life, low power consumption and low maintenance requirements, these factors make LED in outdoor applications become more and more popular. However, the LED is sensitive electronic components, it is easy to switch machines, electrostatic discharges and nearby lightning strikes caused by transient overvoltage and overcurrent damage. In addition, the drive LED does not provide sensitive electronic ballast for LED lighting switch power supply transient overvoltage or overcurrent protection.
In order to meet the needs of high-power LED lighting applications, LED is usually designed to be 5 to 20 in series, because a single LED power heat dissipation problems cannot do very much. The problem was, as long as any one of the series LED fails, it will fail the whole string of LED. Street lamps or runway lighting applications, a string of LED failure may result in the overall brightness of lights dimmed or completely black, cannot imagine security issues. Outdoor advertising LED display applications, this may have white spots, and lead to loss of revenue. In either application, LED a string of failures often lead to costly maintenance issues in outdoor applications.