LED tube power mode

　　Generally only use direct current LED driver , not applying an alternating current or voltage across the LED . Meanwhile, in order to obtain high quality illumination , the LED output and stable, long -life light flux , LED input current to be constant. However, the existing power supply system usually 120V or 220V AC 's . Since the LED can not be directly powered by AC , therefore , to make the LED can be normal, stable job, you must add an AC-DC converter power supply in the front , now widely used in LED lamp switching power is divided into:

　　1 non-isolated constant current power supply : refers to the non-isolated side and the load is directly connected to the input terminal , so there is the risk of electric shock to the touch load , as will the non- isolated power supply AC power to the load pressure introduction side, causing risk of electric shock . Insulation is usually between LED and aluminum radiators will depend film insulation aluminum PCB board . Although this insulating layer can withstand 2000V high voltage , but sometimes glitches screw holes will produce so-called creepage and, therefore , there is a huge risk in terms of security .

　　Isolated constant current power supply 2 : Isolated means at the input and output of the isolation transformer isolation transformer may be a frequency that may be a high frequency . However, both the input and output isolation up . Avoid the risk of electric shock .

　　As the isolated switching power supply in electrical safety on an absolute advantage, therefore , in the field of LED lighting has been widely used , but due to the non- isolated switching power supply isolated power to pay more than a transformer , the transformer and the volume is relatively large , and therefore , Built-in LED lamp isolated power constrained cost and space.