2021-08-25
LED (LightingEmittingDiode) lighting is light-emitting diode lighting, which is a semiconductor solid light-emitting device. It uses a solid semiconductor chip as a luminescent material. The excess energy is emitted by the recombination of carriers in the semiconductor to cause photon emission, which directly emits red, yellow, blue, and green light. On this basis, the principle of three primary colors is used. Add phosphor to emit light of any color. The luminaire manufactured by using LED as the light source is the LED lamp. As a new type of lighting source, LED has the advantages of high efficiency, energy saving and long working life. It has been widely used in various lighting scenes such as LED display, automotive electronics, and life lighting. The LED constant current drive feature requires a specific AC-DC constant current drive power supply. In order to improve the energy efficiency of the power supply, the LED drive power supply generally adopts a single-stage PFC topology.
In the single-stage PFC topology, there is no high-capacity electrolytic capacitor between the input rectifier bridge and the high-voltage MOSFET. In the event of a lightning surge, the surge energy is easily transferred to the MOSFET. The high-voltage MOSFET VDS is prone to overvoltage. At this time, the MOSFET It is prone to avalanches. In switching power supplies, R&D engineers require MOSFETs to have as few or no avalanches as possible.
In applications such as LED driving power supply and industrial control auxiliary power supply, when designing surge protection, power supply engineers can choose higher withstand voltage MOSFETs. Devices with high withstand voltage can block the surge energy at the AC input end and let the input port The MOV protection device to absorb, avoid MOSFET to exceed the safe working area. This can greatly improve the surge protection capability of the power supply of the whole machine.
