Power Supplies

If you want to move, to think, or even to breathe, you need food to supply that kind of energy. The same analogy goes to practically everything else, including electronic projects, we call these energy provider power supplies.

The AC power supply that reaches your home is great for traveling a long distance from the power plant to your home, but there are hardly any electronics that are capable to receive that amount of raw energy without bursting into flames. In order to feed your electronics energy, you need power supplies.

All DC power supplies will go through a step-down transformer first, and then through a full bridge rectifier to convert the high AC voltage to a more manageable DC voltage. This topic is too long to be in the same blog post, read here to understand more!

Different types of DC power supplies

There are two major types of DC power supplies, linear, and switched power supply. Both have their advantages and their technical limitation. In this blog post, I am just going to talk about the step-down power supply. Let us take a look at the linear power supply first.

Linear Power Supply

Nowadays, it is already given that all linear power supply is Low Drop Out (LDO) power supply. The reason why manufacturers want to name their linear power supplies LDO is because of its main technical flaw; its efficiency is really low. What this means is, when a linear power supply wants to convert a higher voltage to a stable DC voltage, it needs a much higher starting voltage to do so, also the voltage it produces might be lower than the expected output because of its efficiency.

When you are converting a higher voltage to a lower voltage, the extra voltage will not just disappear in the thin air. Well yes, it actually does, but as heat. By this logic, due to LDO’s low efficiency, it will need to dissipate more energy into heat, that low efficiency will make the circuit heats up really fast if you are not careful.

Nevertheless, people still use linear power supply due to its simplicity, it is really simple to design an LDO without taking much space or complicated calculation. Read here for more information on how to design your own linear power supply.

Switching Power Supply

The switching power supply is the premium version of the power supply. Its name suggests how the circuit operates, it is really just a switch switching on and off really fast to get to your desired voltage level. It has higher efficiency than its linear counterpart, wasting less energy into heat.

However, building a circuit that can automatically adjust the switching frequency is no easy feat. Switching power supply is known for its complex design to beginners in electronics. Furthermore, switching power supply tends to be more expensive due to its complexity. You will need to source a lot more components to build something of the same function when compared to LDO.

Though when you take some time to learn and understand the electronics in a switching power supply, it is not as hard as you thought. Read here for more information on how to design your own switching power supply.

The Takeaway

Switching power supply is superior to the linear power supply in a lot of ways, however, its cost might be impractical for some design. Due to this, most power supplies, including your laptop adapter, or phone charger uses switching power supply. Linear power supply will usually be used after switching power supply, to obtain more voltage levels in your circuitry without sacrificing space and cost into your design.

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