Why does LED tube light need single-ended power supply?

For LED tube light over the certification, most institutions require a single-ended power supply, but why require a single-ended power supply must be it?

Is double-ended feasible? Double-ended power supply LED tubes, the free end may be charged, how to test this point to determine?

LED fluorescent tubes have been particularly hot lately, with the trend of entering the lighting market to replace traditional lighting.

IEC/EN61195, IEC/EN62031, IEC/EN62471, EN61347-1, EN61347-2-13,

and the EMC standards IEC/EN55015, IEC/EN61547, IEC/EN61000-3-2, IEC/EN61000-3-3, 8ft integrated led tube light.

In the European and American markets, the practice of double-ended placement of drive power

is not accepted in LED fluorescent tube product design due

to the risk of electric shock caused by double-ended LED fluorescent tubes with electricity.

There are restrictions on double-ended LED tubes in the EU, mainly on whether to modify the circuit, please refer to CTL Resolution 0702A.

Although the general organization only accepts single-ended power supply, some European countries are allowed, such as Italy.

Is the drive power supply isolated or non-isolated? There is no restriction on this.

Relatively speaking, the lamp with an isolated power supply, the output power is safe low voltage,

the lamp housing, and hand contact area can be regarded as a safe area, it is easier to pass the safety inspection.

The disadvantage is that the transformer is large, PF value and efficacy will be affected.

When the non-isolated power supply is used, the power input and output are not separated, and the luminaire is regarded as a charged body.

Therefore, the creepage distance and insulation requirements will be higher, including the specific lamp

and foot between the solder joints, the distance between the solder joints and the aluminum substrate needs to be more than 5mm, the distance between the two sides of the lamp beads and the aluminum substrate also requires more than 5mm.

As the same conditions of non-isolated power supply performance advantages are very obvious and lower cost,

if you can meet the insulation requirements and pass the test such as voltage resistance, more competitive in the market.

However, LED fluorescent tube performance and safety regulations seem to be irreconcilable pair of enemies,

when the fish and the bear’s paw can not be both, although, manufacturers will therefore increase the cost of more, personal opinion is preferred over safety regulations.

Market debate on the LED fluorescent lamp power drive there is non-isolated and isolated 2 kinds of non-isolated advantage of low cost, high efficiency (t5 led tube grow light).

The LED light failure, temperature impact is small but require a reasonable lamp structure design insulation is easy to UL,

TUV, CE, PSE. domestic non-isolated power supply over the UL there are 5.

Such as isolated power supply cost is high, the market is not competitive, heat affects the LED life, at least 20% shorter life.

As more components than non-isolated, the failure rate will be relatively high,  efficiency than non-isolated much lower than the general 78-82%, non-isolated efficiency of 87-95%.

Thus, it seems that non-isolated will become the mainstream of the future market has an absolute advantage.

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