September 21, 2023

The Difference between Linear vs Switching Power Supply

Direct current (DC) power supplies have two possible designs. You’ll have either a linear power supply or a switching power supply. The main difference between these two DC power supplies is in regard to how the power is generated in the first place. It would be more beneficial for you to use one power supply instead of the other if the application calls for it.

Linear vs Switching Power Supply

To understand the differences in more detail, let’s examine the specifics of a linear power supply and switching power supply.

Linear Power Supply

The linear power supply manages voltage output with a huge semiconductor device. It uses a power transformer that is connected to the AC line voltage. As the AC voltage enters the transformer, the amount of voltage is increased or decreased in order to accommodate the regulator circuit that it enters right afterwards. A much bigger power supply is usually offered from the linear design because the operational frequency and transformer are proportional to each other.

Linear power supplies are not as energy efficient as switching power supplies because they produce more heat. The generation of this heat has to do with the huge semiconductor device that is used. If a linear power supply is producing 24-volt outputs, then its efficiency level will probably be at about 60%. This is about 20% less efficient than the 80%+ efficiency rating you would find with the switch-mode power supply.

However, linear power supplies have the potential to respond 100 times quicker in comparison to the response time of switch-mode power supplies. So, this is something to consider if you’re dealing with a specialized location that requires a lot of power. Analog circuitry would be a good example of something which benefits more from a linear power supply.

Switching Power Supply

The switching power supply receives AC power and converts it into DC voltage. From there, the DC voltage goes through another conversion where it is turned into a high-frequency AC signal. The regulator circuit receives this AC signal and generates the proper amount of voltage. A small transformer is used to increase or decrease the voltage, but it is not as big as the transformer of the linear design. Despite that, the power conversion ratio is better because these transformers are more efficient.

On average, the size of a switch-mode power supply is up to 80% less than the size of a linear power supply. You might think this is a good thing, and it is to some extent. But the problem is that high-frequency sounds are generated from the power supply. If this power is being used with sensitive electronic devices or equipment, then it could cause a lot of interference with it.

On the other hand, switch-mode power supplies can tolerate minor drops in AC power and not have its electrical outputs affected whatsoever. Any loss within the 10 to 20 ms range is tolerable for switch-mode power supplies. Linear power supplies would not be able to tolerate any amount of AC power loss.

Portable electronic equipment should be powered by a switch-mode power supply. Any piece of electronic equipment that is compact and lightweight is likely going to be suitable for a switch-mode power supply. Since these are not sensitive pieces of electronic equipment, you won’t have to deal with electrical noise or any kind of interference as much with this power supply.

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Hopefully, you have a better understanding of the basic differences between a linear power supply and a switching power supply. If you have any further questions about these power supplies, then you are encouraged to speak with an electrician for additional assistance

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