Comparative Analysis of Isolated Power Supplies and Non-Isolated Power Supplies

2024,09,27

Isolated Power Supplies

Isolated power supplies utilize magnetic components such as transformers to electrically connect the input power supply to the output power supply, so that even if a short circuit occurs at the output, the input power supply and the output power supply are independent of each other, and the output voltage can be adjusted by the transformer.

Non-isolated power supply

The non-isolated power supply does not use a transformer to directly connect the input and output, but through the BUCK circuit step-down, the voltage down, and constant current control, so the most significant advantages of non-isolated power supply is low cost, simple, high performance, but when the lamp is full, if you touch the non-isolated power supply, there is a danger of electric shock, there are safety hazards.

Isolated and non-isolated drive comparison

Theoretically, the fewer components in an electronic circuit, the higher the reliability. But why are non-isolated power supplies less reliable than isolated power supplies? The reason is that non-isolated circuits are very sensitive to power surges, but have poor suppression capabilities.

The isolated power supply is to input power into the transformer first, and then into the LED load, while in the non-isolated circuit, a part of the input power supply will be loaded to the LED, so the isolation circuit is better suppression of power surge, and less damage to the LEDs than non-isolated circuits, which is why most of the people in the market ask for the use of isolated power supply.

Non-isolated drivers are more efficient and less costly than isolated drivers. Isolated driver efficiency has been difficult to achieve, and performance at high temperatures is not good, the cost is also higher.

Surge damage to LED drivers

Non-isolated power supply damage is caused by the surge voltage of the AC power supply, under the action of lightning, the AC power may appear in a very large voltage, very strong power, a short period of time can be up to 3000V, it will be straight to the output in the BUCK circuit, damage to the constant-current detection ring, and even damage to the LED chip, which will form a breakdown of 300V, burned out the lamps and lanterns.

80% of the LED drivers in the use of the process will fail, as well as other small switching power supplies, are damaged because of power surges, LED driver is damaged because of the load characteristics of the LED itself, very sensitive to such power surges.

But the power surge problem does not only exist in the non-isolated power supply, isolated power supplies also exist in the same power surge problem, a lot of isolated power supplies, such as outdoor street light power supply, in the use of a short period of time will be damaged because of power surge. With the development of new technology, non-isolated power supply has matured and stabilized, if the structure is properly designed, it can be completely used as a power supply as safe as isolated power supply.

Different applications of isolated and non-isolated drivers

The following are some references for using LED drivers, which are summarized from years of experience.

For high power LED drivers, isolated drivers are safer, and non-isolated drivers may have the risk of being overweight.

For low power LED drivers, the decision should be made on a case-by-case basis. If using non-isolated driver, two points should be considered: a) cost allowable, b) available heat.

Non-isolated power supply is suitable for applications: a) indoor lighting, power stability, less affected by power surge. b) high voltage and low current, low voltage and high current, efficiency and cost can not benefit from non-isolated power supply. c) voltage stability.

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Author:

Mr. Owen

Phone/WhatsApp:

+86 13923144845