1. Background: LED semiconductor lighting as a new type of industry, the current certification of reference standards can not meet the rapid development trend. The first version of the UL870 released by UL on November 18, 2009 provides the industry with a standard for the safety of LED lighting devices. In UL8750, the power supply or power driver (LED Drivers) can be selected to use the CLASS 2 power supply that meets UL1310, the power supply that meets the requirements of information technology safety UL60950-1, and the CLASS 2 power supply other than the UL1012 standard. The electrical structure of the light source luminaire can be exempted from more electrical test items for the CALSS 2 power supply and LVLE circuits. Although the EU has not yet developed a safety standard for LED Light source products, some countries in the European Union (France, Denmark, etc.) have begun to require LED road lighting to meet CLASS 2 power supply. Although domestic LED outdoor lighting fixtures have UL certification, they basically use the UL60950 standard certified power supply. With the in-depth development of the LED semiconductor industry, the use of CLASS 2 power supply for LED light source products is a future development trend. 2. What CLASS 2: UL60950-1 (General Safety Requirements for Information Technology Equipment) classifies electronic equipment into three categories: CLASS 1, CLASS 2, and CLASS 3 according to the degree of protection against electric shock hazards. CLASS Class 1 equipment refers to other protective measures such as grounding in addition to the basic insulation. CLASS 2 equipment refers to not only relying on basic insulation, but also adopting double insulation or reinforced insulation as electric shock protection measures. The protection effect does not depend on protective grounding or installation conditions; CLASS Class 3 equipment refers to the use of exceptionally low safety voltage (SELV) for power supply and no hazardous voltage generation. The CLASS 2 power supplies covered by the UL8750 and UL1310 standards are all compliant with the UL60950 CLASS 2 equipment against electric shock safety. 3, CLASS 2 power supply definition: Class 2 Power Source, defined by the LED Lamp safety standard UL8750, is an isolated power supply that meets the requirements of the UL1310 standard (UL1310 is a safety standard for CLASS 2 power units for indoor and outdoor use) or UL5085- 3 required low voltage Class 2 and Class 3 transformer powered circuits. UL1310 defines CLASS 2 POWER UNITS as: IEC/NFPA70, connected to 15A or 20A 120-240Vac branch circuit with less than 150V ground, with insulated and isolated transformer for DC and AC Energy, intended to provide energy to low-voltage, electricity-operated devices. And the CLASS 2 power supply is a device with limited output voltage and energy capacity. Under any output load, the input power does not exceed 660W. UL1310 stipulates the assembly mechanical structure, performance test requirements and product labeling of CLASS 2 power supply. The following is the analysis of the main electrical performance requirements and test specifications of CLASS 2 power supply, and provides relevant UL certification for power supply modules for LED light source lamps. reference. 4. Voltage limits for contactable live parts of CLASS 2 power supply: The output of the CLASS 2 power supply unit specified in the UL1310 standard shall be provided with an output cord, terminal block, insulated lead or output terminal. After the protective cover, the partition or the protective tool that can be removed without using the tool, after the removal, according to different test needles (Fig. 1), the joint detector (Fig. 2) or the tactile detector (Fig. 3) The degree of contact with live parts has different requirements for the maximum voltage at the output. Before testing, it is necessary to confirm that the uninsulated live parts must be fixed on the surface of the substrate or the fitting. The minimum acceptable spacing cannot be caused by the occurrence of swirl or displacement. At the same time, the live parts that may cause the call to be dangerous must be enclosed or placed. Access to dangerous places. 4.1 CLASS 2 power supply exposed terminal maximum contact voltage requirements and test methods: The maximum voltage of the live parts that can be accepted by the CLASS 2 exposed terminal is not more than 25N (5.62 lbs) using the detector (shown in Figure 2). Do not touch the detector with more than the following voltage: 1) Sinusoidal or non-sinusoidal AC peak 42.4V; 2) continuous DC 42.4V; 3), equal or less than 200Hz frequency, DC current peak of about 50% duty cycle 24.8V; 4) DC and AC mixing peak 42.4 V;
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