power modules tutorial

The different types of electronics power modules tutorial and how to choose the right one for you.

If you click on our power supplies and modules category you will see many different power supplies and modules, there are adjustable ones, buck, boost, step-up, step-down, constant current, low power, high power and the list goes on and on. Hence this power modules tutorial.

The one thing all these different units have in common is that they all manage/change power in one way or another. Usually, they change a high voltage to a lower voltage, most commonly used power supplies also change AC current (from your house plug for example) to DC as required by most electronics. The popular 12V power supplies used on Arduino’s are a good example that changes AC to DC and lowers the 220V Volts to 12V

A power supply is a complete unit with wires inside a case where a power module is just the electronic circuit board.

Raspberry Pi Power Supply LM2596 Adjustable Step Down Power Supply module DC

In the rest of this power modules tutorial, I will refer to power modules but it is the same for power supplies.

The amps a power module can handle are probably the first thing you will look at when getting yourself one.

When developing projects we need more than a mere 12V power supply, we need to supply different power to different parts of a circuit and change it in ways to charge batteries and all kinds of other thigs, hence the big range of power modules.

When working with these modules you will often can a module that is bigger than the required input e.g. 12V for an Arduino Uno although all components require 5V and then from this supply make the voltages less as you go along.

Power usage

Once you decided on the voltage you will require you will need to think about the amps you will need. You need to understand that a voltage is supplied by a power supply and the wrong voltage will destroy your components but the amps it uses are drawn from the supply as needed by the components. Different components need more power than others.  One component might need 12V and 100mA and another 12V but 300mA. Together they will require 400mA.  The formula for power is V x A, thus you will need, in this example 12V x 0.4A thus a minimum of 4.8 Watt of power. Becuase amps are not ” pushed” into the circuit like voltage but “pulled” in as required by the components you can and should use a supply that can provide more than the required amps like a 1A supply. You want the supply to not work at its highest rating as to not put an unnecessary strain on them. An over worked unit will be very hot to the touch, a unit with amps to spare will be slightly warm to the touch.

Step-up, step down, buck and boost.

The word “buck” had me a bit confused when starting with these modules until I figured out it is just another word for step-down. A step-down unit just means you are going to make the volts less. This is done with a voltage regulator IC.

Boost is another word for step-up, this means you are going to make the supplied voltage more. This is done with devices called inductors.

To further explain these modules I will discuss a couple that is often used, why you will use them and shortly how to use them. As we explore some of these modules you will also learn about adjustable and constant current modules.

Adjustable 3A Ultra small power module

The most basic buck module, its small, can handle quite a big amount of current and its voltage can be adjusted.Adjustable 3A Ultra small power module

Way to the top right-hand side in the picture you can see the holes where you can connect your power source. The left side is where the adjusted power will be available to connect to your circuit. You should see the little adjustment pot that you will adjust to the correct required voltage, it’s the component near the bottom right next to the “+” sign.

This module is small but can deliver up to 3A and can adjust power sources between  4.5V to 28V down to
0.8V to 20V.

It is important to note that this unit itself uses a bit of voltage (as does most) to do the adjustment, normally around 0.8-2V, the higher the voltage is to adjust the more volts it uses itself.  You will thus need a voltage input that is 1-2V higher than what you want the output to be. If you use a 5V input you should easily get the unit to adjust between 0,8V and 4.2V, a 12V input 0.8V – 11V and so on.

to adjust these modules you need to hook it up to power and then use a multimeter on the output side to adjust the screw to the correct voltage.

You can look at the full specs here.

Adjustable Power step down module with Voltmeter

Next up is a similar module then discussed above, also a buck module,  but this one comes with a voltmeter for easy adjusting the power output without the need of a multimeter.

LM2596 Adjustable Power Converter

In fact, if you use a 12V 2A power supply with this product you have quite a neat desktop power supply. It has 2 buttons so you can check both the input and output voltages on the screen and small LEDs indicating if you are looking at input or output volts. These types of modules are best used as power sources while doing development, not final products (like the one discussed previously) except if your project will need a permanent voltage meter. I use them all the time while developing and testing products and the screw terminals are very useful to attach different products without having to solder them.

If you look at the components on this board you can see there is quite a difference compared to the first ultra small board we looked at. The main thing is that the ultra small board is as basic as they come to make the board as small as possible to incorporate them into final products. This board we look at right now is more expensive and another reason why I use them just as desktop power units to save on costs on final products.

However, they also use more powerful voltage regulators that can handle up to 40V input and 37V output for bigger voltage projects. It also has bigger stabilising capacitors that are very useful to have while developing higher voltage projects, stabilizing caps help to keep the output voltage very smooth even if the input voltage is not.

You can get all the specs for this module here.

AC-DC 220V to 12V power module

You do not need a bulky 220V to 12V power supply, especially if you are going to have a low power design.

This module takes 220V AC on the one side and supplies 12V DC on the other side. A WARNING though, you work with 220V power, it can kill you! But these modules are great when you insert them in your home build PC boards to make things look neat. I do not recommend them to new comers but introduce them here as part of the power modules tutorial as education. From this output, you can then add. for example. an ultra small step-down module to get the volts exactly where you want it to be just as you would with a normal 12V power supply.

More about these units here.

This concludes our look at basic power modules Next week we will look at more advanced modules in part 2 of this tutorial.

 

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