Switching Power Supply VS Linear Power Supply

Switching Power Supply VS Linear Power Supply

When it comes to electronic circuits, it is essential to have the right type of current flowing through the circuits without crossing the limits. The switch-modeand linear designs are the two main types of DC power supplies used to supply current to electrical circuits.

While both of them supply DC power, the method used in generating power is different. Each type has certain unique benefits that further distinguish them from the other.

A switch-mode arrangement covers the AC line power into a DC line without the need of any transformer. This raw DC voltage is changed into an AC signal with higher frequency to be used in theregulator circuit. It helps in producing the required voltage and current. So, what we get is a much smaller transformer to increase or decrease the voltage.

These small and compact sized transformers are also much more efficient than 60 Hz transformers. So, this means the power conversion ratio is pretty high.

A linear design on the other hand is used to convert the AC line voltage into a power transformer in order to increase or decrease the voltage. As the transformer size is dependent on the frequency of operation, you get a bulkier form of power supply.

Both these types of power supplies come with their own unique set of benefits and downsides. The switching power supplies are about 80 percent smaller and lighter than the linear power supply. Despite being smaller in size, they pack a lot of power. Switching Power Supply VS Linear Power Supply, eitherway, they can generate high-frequency noise which can inhibit the sensitive electronic equipment.

Unlike the linear design of power supplies, the switch-mode types can endure small losses of AC power that fall within the range of 10-20 ms without impacting the outputs.

The linear power supply on the other hand needs much larger semiconductor devices to control and regulate the output voltage. Thus, it is capable of producing more heat which results in low energy efficiency levels.

The linear power supply usually operates with about 60% efficiency for 24V outputs, while the switching types are capable of operating at 80%more. The linear power supplies come with transitory response times which are much faster than switching counterparts.

The switch-mode power supply is suitable for portable equipment as it is much lighter and more compact in size. The linear supply is suitable for the powering-sensitive analog circuit as the electrical noise is much easier to control.

What are the main differences between the two power supplies?Switching Power Supply VS Linear Power Supply

  • Size and weight: The heatsinks used in the linear type of power supplies add more bulk to them. Transformers used in this form of arrangement are also larger due to low operating frequency. The switch-mode power supplies are compact as they use smaller transformers due to high operating frequencies.
  • Output voltage: With a transformer, you can use any type of output voltage with a linear power supply. Without a transformer, you are limited to what can be achieved using a voltage doubler. The switching power supplies, on the other hand, can comply with any type of voltage available. They are restricted only by the transistor which may reduce voltages in many circuits.
  • Efficiency and heat dissipation: When regulated, the efficiency largely depends upon the difference in voltage between input and output. The output voltage is mainly regulated by dispelling excess heat so the resulting efficiency comes around 30–40%. In the switching power supply unit, the output voltage is regulated using the duty cycle control. The transistors are either fully switched on or switched off so you lose very little energy when switching between the loads.
  • Electronic noise: In case of a linear arrangement, the unregulated PSUs may have a slight AC ripple which is superimposed on the DC component. This causes the audible mains to emit a slight electronic hum in the audio equipment.The switch mode types are noisier because they come witha switching frequency. If there’s an unfiltered output then this might result in malfunctions in the digital circuits or produce noise in the audio circuits.

Conclusion

To sum it up, a linear design supplies constant voltage while a switch-mode power supply can’t. The linear design is also much simpler than its switching counterpart. On the other hand, the switched mode power supply provides a better power efficiency than linear supply. Hence the latter is widely used in computers and other electrical appliances.

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