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What is the difference between isolated and non-isolated driving power supply

In the led lighting market, there are driving power supply isolated and non-isolated led lightings.
Non-isolated design is just for Double-insulated products just like the replace product for bulb. Led and the whole product are integrated and sealed in the non-conductive plastic, so the user don’t meet the dangerous of electric shock. The secondary products are all isolated. It is more expansive, but it is necessary for the user to touch led and output cable (usually for led lighting and street lighting cases).
Isolated bulb will be the main stream in the future.
The physical design decides if the driver is isolated or non-isolated. Safety standard usually requires two independent insulations. The designer can choose two kinds of physical insulations. That is plastic diffuser and glass shield and use non-isolation driver power supply. If the physical isolation cost is high or there is mechanical problem or absorb too much light, then the problem of isolated driver must be solved. The isolated driver power supply is bigger than the non-isolated one. Lighting designer must consider the cost and design improvement in every kind of products.
The cost of driver with transformer is higher, but this will make the led lighting more practical. It can make end user touch the led when need. When the glass shield of incandescent bulb is broken, a E27 simple bulb can be replaced with led lighting. Moreover, in the industrial area or office, end user don’t have chance to be touched by end user. But these applications also need the led lighting with isolated transformer.
To be a safe product for end user, the reliability of insulation and isolation must be considered. For the whole finished product, the surface which the user can touch must be isolated to avoid electric shock. From the whole product system, isolation can not be avoided. The difference is just the isolated area. Some designer adopts isolated transformer design, so they can simplify heat conduction and the lamp cover design. If they adopt non-isolated design, they must consider the insulated requirement for the lamp body. So for the power supply driver, isolated and non-isolated power supply exist together.
Based on transformer insolated Led driver power supply will be the main stream.
There is advantage for both isolated and non-isolated driver power supply. We believe that Class II would be the main stream as it simplifies the led cooling condition. Class I or II rely on earthed system. Usually, it matters the installing location. Class II is normal. It requires double or strength isolation. That means it needs transformer magnetic winding, insulating tape and physical isolation. Class I system requires a earthed case or dysfunction. But these are not needed for Class II system.
At present, there are several trends to push led lighting market to develop. First is the improving of high brightness led efficiency and the coming forth of very high efficiency and reliable constant current driver power supply. Second is that incandescent lamp is forbid (because of low efficiency) and CFL energy saving fades step by step (If it is broken, the mercury will outflow.). All these elements makes led lighting becomes the long development trend. Of course, low system cost (including led, heat management system and led driver) will always be the customers driving force to adopts the led widely.
In fact, in most of the led lightings, being invalid is normal. It is mainly for the invaliding of the power supply but not the led.
From design aspect, this means that OEM must be system heat design expert. Led provides high efficiency, but they also produce more heat than incandescent lamp and energy saving. As many led lighting application is sealed in very small space, it is very hard for heat conduction by air. If without detail heat design, led and power supply driver circuit will become vestigial or invalid because of high temperature.