Arduino 5V power supply

Everything in nature requires a source of energy. Arduino is no different. In the market we can find many different DC power sources, among those most commonly used are batteries, 5V (USB), 12 V and 24 V. Many more exist, but these represent the vast majority.

I had a (technical) problem, where I was using Arduino to cycle a pneumatic cylinder, but in an industrial environment. There I can always find 24 V DC in some corner or another, but 5 V, as Arduino requires is not that common. Hence this sub-project.

References

  1. Jameco LM2575T datasheet: https://www.jameco.com/Jameco/Products/ProdDS/894534.pdf
  2. Texas Instruments LM2575 datasheet: http://www.ti.com/lit/ds/symlink/lm2575-n.pdf

Possibilities

How to step-down 24 V to power up Arduino? There are at least two ways to my knowledge:

  1. Linear voltage regulator, such as LM7805 and
  2. Switching voltage regulator, such as LM2575T.

The first is inefficient — it heats up a lot. The second is efficient, but it produces some high-frequency noise.

Let’s see, how we can use the second type, LM2575T to make a very cost-effective Arduino power supply.

Design

There is not much to invent in this case, so I can only refer to the schematic on page 2 and 1 of datasheets from Jameco and Texas Instruments respectively. The schematic is shown in Figure 1.

Figure 1: 7…40 V DC to 5 V DC 
± 4% switching power supply schematic.

Bill of materials

For this project you will need the following material:

  1. LM2575T switching regulator (1 pc)
  2. 100 µF capacitor (1 pc)
  3. 330 µF capacitor (1 pc)
  4. 330 µH inductor (1 pc)
  5. 1N5819 (also 1N5817) Shottky diode (1 pc)
  6. PCB or protoboard (1 pc)

All together will put a dent of approximately € 0.46 in your pocket, if you get a great deal. Without the PCB that is.

Conclusion

It doesn’t matter, if you can buy a power supply for Arduino on Aliexpress for less than $1.00, this project is more about making something and being satisfied with yourself. You can also integrate this project with your other projects and get a compact, more professional PCB. Why not trying to sell one of those then? 

If you need a cheap and efficient 5 V power supply for your micro-controller, I think the LM2575 is a great choice. It will work much more efficiently than linear voltage regulators, which means less energy consumption and heat loss. This is an easy project, I would say, and I think that you should tackle this yourself, to learn a few basics.

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