Hello, how are you going? My name's Sam and I'm from Core Electronics and today we're going to be taking a look at how to use DC regulators and converters. They're sort of one and the same thing.

Now what is DC first of all? If you're not familiar with some of these terms like DC, which stands for direct current, then check out our Analog Electronics Crash Course tutorial first because it covers off on a lot of the basics of electronics like voltage, current, ohms law, and the basics of components.

But today we're going to be taking a look at a few different types of converters and regulators and how you can use them in your project.

How do they work? Well, first of all, a bit of a term clarification. You'll hear a few terms come up in this tutorial that you might want to get a grasp on.

First of all, we've got load regulation. Now this defines how much the output voltage changes with regards to the current being drawn from the output. So a regulator that has a really good load regulation means that when it starts drawing more current, it's still going to deliver the same voltage. It's not going to sag according to ohms law.

Second of all, we've got line regulation. Now this term defines how much the input voltage changes affects the output. So if you're supplying a converter with say five volts and you've got 12, it's a step-up converter and you've got 12 volts on the output. Now if you get changes in the input voltage, is that going to affect the output voltage or is it going to remain pretty constant and stable? And will it do that under load? Things like that.

Now you've also got dropout voltage. Now on a regulator such as a step-down regulator, you've got what's known as the dropout voltage and that is the input voltage can be above the output voltage. So it's a bit confusing, but say for example we've got a five volt regulator. Now this is an L7805 five volt linear regulator and the dropout voltage for it is a couple of volts above the output voltage. So if you have 12 volts, it's going to output the five volts. But say the dropout voltage is two volts, that means that your input voltage can be no lower than seven volts because it's the dropout voltage above the output voltage before you start running into issues.

So now we've got that out of the way, let's dive into what are regulators and how do they work.

Well we've got two types of regulators. Linear regulators and switching regulators or switch mode regulators or converters. We're using the term interchangeably here. Now these are just different methods for converting voltages and we'll get into how they actually work in a minute. But it is important to note that they're different products. You can't just say that one is a linear regulator when it's actually a switching regulator because they operate differently.

A linear regulator uses a pretty simple circuit and it essentially dumps the extra voltage. So say you're converting 12 volts down to 5 volts. Well a linear regulator usually will have an operational amplifier in it or loading components inside of here to drop that voltage down to the 5 volts. But a switching regulator actually has a PWM signal driving a really really fast electronic switch on and off thousands of times per second. Now this is really good because unlike a linear regulator there's no components in there to introduce, well little components, so you know very few components in there to draw a very slight load on the regulator which means the switch is either always on and there's no on resistance or it's off and there's you know maximum resistance, no current can flow, which means that unlike a linear regulator these are very very efficient power-wise, a lot less wastage and power losses during the conversion.

Now within regulators there's two, well three terms that you're going to hear thrown around. You've got buck, boost and a combination of the two, buck-boost. Now these terms are simply whether it's a step down regulator or a step up regulator and how the circuit works. So a buck regulator is designed to drop the voltage, it's a step down regulator or converter, so say you have a 12 volt input then that is going to give you say a 5 volt output or you know it's a set 5 volt output you can supply 12 volts, 18 volts, 24 volts, whatever, it is a buck switching regulator. Now if you have a boost switching regulator that means you're stepping up the voltage so it might be a 12 volt output and you can give a variable input voltage between say 3 volts and 9 volts or whatever. Or a buck-boost regulator is one that can do both which is really cool, you give an input voltage it can give you a wider range of output voltages both lower and higher than your input voltage which is really really cool.

So we've got these two different types of regulators, now there's also a third type of regulation that we haven't covered which is zener diode. Now a zener diode acts like a regular diode, it acts like a valve except that it has a special property called a zener voltage. Now what this does is normally when you would use a diode it is forwards biased which means current flows in one direction and then the other direction it doesn't allow current flow, well with a zener diode you can actually reverse bias it and once that voltage, the reverse voltage reaches a certain point, reaches the zener voltage, it'll conduct as well which is really really cool because you can use them to put a quick easy dirty regulator on a project just if you want to you know test out test something out. So what you could do is you have a 12 volts, we've got a diagram in the tutorial, you have a 12 volt supply and you might have a zener diode that has a zener voltage of 5.1 volts. Now you could put this so that it will never conduct, never always conduct so you're reverse biasing it and then as soon as that voltage gets above 5.1 volts it's going to dump that to ground and it gives you a nice fairly stable 5 volt output but there are some issues with this, you get you know you can get sags in your voltage, it's not ideal, it's a quick and dirty method. A good linear regulator or switching regulator is going to be what you want.

So now we've discussed some of the I guess the trade-offs, switching regulators are more expensive but they're much more energy efficient, a linear regulator is less efficient but they're a lot cheaper.

Something to be aware of as well is that switching regulators because they're switching very rapidly on and off you can actually get some of that noise into the power line. Now that's fine if you're using a digital circuit with plenty of filtering and all the rest and you know it's quite safe but they don't recommend using switching regulators for audio circuits because you can actually hear that switching noise, that frequency is low enough that it can be heard by the human ear and if you're using that in an audio circuit it can actually transfer into your audio signal which is not ideal, not ideal at all.

So which one is better? Well switching regulators are fantastic if you want efficiency, all about efficiency. For example these guys will often handle a main signal and this is the primary method of getting a main signal so 240 volts here in Australia, 120 volts here in other places, down to say a 5 volt supply like you would find in a laptop charger or a cell phone charger. Because once you use a rectifier to get rid of the AC current you're just left with 240 volts in DC you can then use a switch mode supply and even though there's this huge gap, this huge change in voltage, because these are so efficient there's less heat. Linear regulators are a popular choice for stepping down voltages, especially for small projects. However, they are not very efficient and can result in energy wastage, particularly when there is a significant voltage difference. In contrast, Pololu regulators offer high quality and versatility, with the ability to adjust output voltage manually or through a digital interface. It's important to consider the efficiency curve when using these regulators, as it varies based on the relationship between output current and input/output voltages.

When selecting regulators for a project, it's crucial to avoid cascading voltage conversions, as this can lead to significant energy losses. For optimal performance, it's advisable to use separate regulators for different voltage requirements rather than daisy-chaining them. By referring to the datasheet, one can determine the most effective use of regulators and converters for their specific project needs.

In conclusion, regulators and converters play a vital role in electronic projects, offering a cost-effective solution for voltage regulation. By understanding their efficiency and technical specifications, one can make informed decisions to maximize the performance of their circuits. We look forward to seeing the innovative projects created using these essential components. Happy making!