At present, in the general led lighting market, there is a non-isolated design and isolated drive power supply.

    Non-isolated designs are limited to double-insulated products, such as alternatives to light bulbs, where the LED and the entire product are integrated and sealed in a non-conductive plastic, so there is no risk of electric shock to the end user. Secondary products are isolated and relatively expensive, but where the user has access to the LED and output wiring (usually in the case of LED lighting and street lighting applications), this product is essential.

      LED drive power with isolation transformer or electrical isolation means that the LED can be touched directly by hand without electric shock. Although the LED drive power without isolation transformer can still be partially mechanically insulated with the help of the protective housing, the LED at this time cannot be directly contacted when working.

    Insulated bulbs will become mainstream in the future

    The physical design determines whether the drive is isolated or unisolated. Security rules typically require the use of two separate isolation layers. Designers can choose between two physical isolation layers, namely plastic astigmatism cover and glass shield, and use a non-isolated power supply. If physical isolation is too costly, mechanically difficult, or absorbs too much light, electrical isolation must be addressed in the power supply. Isolated power supplies are generally larger than non-isolated power supplies of the same power level. Lighting designers have to do a lot of cost and design optimization work in every product they design.

    Because it is suitable for different applications, whether to use isolated insulated transformers or isolated protective lampshade housing, designers will always have different opinions in different perspectives. Usually, they will look at many aspects, such as cost and manufacturing process, efficiency and volume, insulation reliability and safety requirements, and so on.

    The drive cost with transformer is higher, but it also makes LED lamps more practical and can meet the needs of end users who occasionally come into contact with leds. When the incandescent glass case is easily damaged, an ordinary bulb of model E27 can be replaced with an LED lamp. In addition, lamps in industrial areas or office equipment applications do not need to touch the end user, such as street lights and shopping mall lighting, and LED lights do need isolation transformers at this time.

    As a product for safe use by end users, the reliability of insulation and isolation must be considered. As a complete product, the part of the product surface that the user can access must be isolated and cannot be electrocuted. From the perspective of the entire system of the product, isolation is inevitable, the difference is that the location of the isolation is different. Some designers use isolated transformer designs, so they can simplify the design of heat dissipation and lampshades. If a non-isolated drive design is used, reliable insulation requirements must be considered in the lamp housing and other structures. Therefore, as a power driver, isolated and non-isolated solutions have always existed at the same time.

    The main challenge that Chinese LED drive power manufacturers may face is to find low-cost AC/DC drivers to meet the more stringent power factor and efficiency performance in low-cost power systems.

    In the future, the use of high-quality, highly reliable power supplies in space-constrained and difficult cooling systems, such as LED lamps, will no longer be free. However, until the end user has used many bulbs with a lifetime of around 10,000 hours, it is quite difficult to prove their high quality.

    Transformer-based isolated LED driver power supply will be the mainstream.

    Isolated and non-isolated LED driver power solutions have advantages and disadvantages. We think the ClassII will be mainstream because it simplifies the LED heat dissipation problem. ClassI or II systems rely on grounding systems, which, in most cases, depend on the installation location. ClassII is more common and requires two-stage or enhanced isolation, i.e. transformer magnetic windings, insulating tape, and physical isolation. The ClassI system requires a grounding enclosure and/or mechanical barrier, which the ClassII system does not need.

    There are several trends that are driving the development of the LED lighting market. The first is the continuous improvement in the efficiency of high-brightness leds and the continuous emergence of highly efficient high-reliability constant-current LED driver power supplies, followed by global legislation banning incandescent lighting (due to its low efficiency) and the gradual fade out of CFL energy-saving lamps (if broken, it will emit mercury harmful to the environment). These factors combined are making LED lighting a long-term development trend. Of course, low system costs (including leds, thermal management systems and LED drivers) will always be the driving force behind widespread consumer adoption of LED general lighting.

    In fact, in many LED lighting products, failure is a common phenomenon, mostly because of the failure of the power supply, not the failure of the LED.

    On a design level, this means that Oems must become experts in the thermal design of systems. Leds offer high efficiency, but they also produce more conductive heat than incandescent or CFLS. Because many LED lighting applications are closed in a small space, it is difficult to use ventilation to dissipate heat. Without careful thermal design, leds and power drive circuits can easily degrade or permanently fail due to high temperatures.