5V Regulator design tutorial - How it works, how to design PCB altium

this is what happens when we supply too much voltage to our electronic components the components will burn out and even explode to stop this we need one of these a voltage regulator and i'm going to show you how it works how to design one and even turn it into a fully working professional looking printed circuit board to use as a power supply and even charge a phone with it you can even download a copy of my circuit board to links in the video description down below for that the purpose of a voltage regulator is to keep a constant output voltage even when the input voltage changes why is that important because the electronic components are only rated to handle a certain voltage take this led for example if we connect it to a 9 volt battery it will instantly be destroyed forever that's because of this thin wire inside the led looking under a microscope we can see the voltage pushed too many electrons through the wire which caused it to burn out to protect the led we need a resistor this will reduce the current this is only a 10 ohm resistor which is connected to my variable dc power supply when we apply a small voltage we see the led is fine but as we increase this the resistor bursts into flames and the led will be destroyed so using a resistor works well but the voltage must remain fairly constant we therefore need a way to ensure a constant output voltage even when the input voltage is varied let's say we want to maintain a constant 5 volt dc supply and enough current to charge a simple cheap phone we want to be able to connect this to multiple voltage sources such as 9 volts or maybe 12 volt batteries to achieve that we need to use an integrated circuit component there are lots to choose from which can all work in different voltages but from a bit of research i found this one the lm7805 this can maintain a constant 5 volt dc output and up to 1.5 amps of current this component can be connected to any dc supply voltage between 7 and 35 volts so it's perfect for our needs it has 3 pins pin 1 is the input for unregulated voltage pin 2 is the ground pin and pin 3 is the regulated 5 volt output the manufacturer recommends a capacitor on the input and the output it notes that the input capacitor is required if the regulator is far away from the power supply filter we are going to be using some long wires to connect the battery so we will use the recommended 0.22 microfarad capacitor this is an electrolytic type capacitor we can use a slightly larger capacity version but we don't want to use a smaller one the capacitor is going to help smooth out interruptions to the supply and also low frequency distortions in this simple example you can see the led turns off instantly when the power is interrupted but if i place a capacitor in parallel with the led the led will remain on because now the capacitor is discharging and powering the led so the led is almost unaffected by the interruptions we're going to add another capacitor in parallel on the input side this is a bypass capacitor this is placed very close to the regulator input pin this will be a small ceramic capacitor which is typically 0.1 microfarads the purpose of this capacitor is to filter out the noise and high frequency distortions from the power supply as we might not always get a perfectly flat dc supply we will also add another 0.1 microfarad bypass capacitor on the output side as well as a 10 microfarad electrolytic capacitor this is just a typical value used for this purpose we could use a slightly higher capacity version if we wanted to but this will work fine these are going to help ensure we have a clean output on our connected circuit we will also add a protection diode on the input side this will help protect the circuit if we connect the power supply the wrong way to show how it works if i connect this incandescent lamp to a power supply it will illuminate i can reverse the leads and it will also illuminate if i place a diode on the red wire and connect this to the positive it will again illuminate but now when i reverse the leads the diode blocks the current and the lamp remains off so we can use this to protect the circuit we can use a rectifier diode or a schottky diode here you can see i have placed two leds each connected to a different type of diode as i slowly increase the voltage we see the led connected to the rectifier diode is not as bright that's because this type of diode has a large voltage drop if i measure across the schottky diode we have a voltage drop of around 0.3 volts and the rectifier has around 0.66 volts so it's better to use a schottky diode for this application now we can lay all these components out on a breadboard to test it out like i've done here and once we're happy that it works we can now turn this into a printed circuit board we're going to be using altium designer for this tutorial as they have kindly sponsored this video all our viewers can get a free trial of this software using the link in the video description down below so open ltm designer and click file new project then give the project a name right click the project and add a schematic then right click again and add pcb now right click the schematic and save this give it the same name as the project then also right click the pcb and save that to with the same name now we need to add the components we can use the components tool on the right hand side but i'm going to use an add-on which will make this a little bit easier so we find the parts we require i'm using mouser but you can use whoever you wish i found a 22 microfarad capacitor so i take this part number and insert this into the library loader and click search it then finds the component so i click add to design it will place the component in the lower corner so i just need to move it into position then we rename the component just to make it easier for us now we do the same for the other input capacitor copy the part number and search for it then add it move it and rename it then we find the regulator and we add this to our design and then we find the protection diode and we add this to our design by the way i'm using this one but i would recommend you choose one with a higher current limit and then we find the output capacitor we add this and then we rename it we now need to find the connection terminals and we add this to we need another capacitor on the outlet so we select the existing one and copy and paste that and then move that into position and we do the same for the connector type on the input side now we just rotate the components so select the input connector and press the spacebar to rotate it then we rotate the diode then we can rotate the capacitors but do make sure that the plus symbol always goes to the positive power supply the other ceramic capacitors do not have a polarity so these ones can face either way but we'll keep it in this order then we rotate the regulator and we'll also move the text then we rotate the next capacitor and the other capacitor and then we just move the components into position now click the wire tool and start to connect the components together bringing the ground wire around to the regulator then we add a ground symbol to this wire now use the wire tool to connect the output side as well now add the annotation for the input supply which is vcc then add the annotation for 5 volts on the output side and rename this we can also add some text for the output voltage and also the input voltage too now we need to number the components so click tools annotation annotate schematic then select down then across and then update the change list click ok accept the changes then validate the changes then execute the changes and close now we see the components are all numbered next we need to validate the design so click project and then validate project if we click view panels and then messages it tells us the compilation was a success with no errors so now click on the pcb and click design and then import changes then validate the changes and then click execute changes the components are placed in the lower corner just click the box and delete it looking at our schematic we have the connector j1 on the input so we'll move that then we have the diode and capacitor 1 and capacitor 2. so we'll move these into position also then we have the regulator then we have capacitor 3 and 4 and then we have the output connector we now rotate the components to make the route for electricity to flow we can switch to 3d mode to check how it looks then we can align the components to improve the appearance now click down here and in the new window select mechanical layer right click and create new layer and name it cutout change the settings and then close now select your layer down the bottom then click edit origin and set then click the top corner of the circuit board now click place and choose line draw a line around the components then while holding shift click on the four lines then click design board shape and define shape we can then also see it in 3d now i'll just change the text size so it doesn't print too big now click on top layer and then insert some text and we'll name this 5 volts and we can just rotate that we'll also do the same for the ground text looking at the input side of the board i've just realized the input connector is the wrong way around we can see that in the 3d view i just missed it earlier so i'll just correct that now then we add the ground and the vcc text to the board now click root auto route and select all it then adds our route to the board we can also move the route if we want to now we go to tools and rule checker click run it loads a report and tells us that we have two problems on the silk and solder mask clearance we go design rules silk to mask then change the value click apply ok then run the rule checker again now we see there are no errors we can see the route in the 3d design now also so let's save that click on your schematic and then click file smart pdf then choose the schematic i'm turning off the bill of materials but you can leave this on if you want to click finish and it generates a pdf of our design close that then click on the fabrication output choose gerber files and then choose the project now click that and change it to millimeters then on layers you can leave this as it is but i'm going to select all the layers and click ok click on folder structure and then link the file and click generate and that's it we're done we are ready to have our circuit board printed now we need to order our pcb i'm using jlc pcb who have also kindly sponsored this video they offer exceptional value with five circuit boards for just two dollars i'll leave a link in the video description down below for that do check it out i'm just changing the shipping destination and currency to the uk as that's where i'm based but you can choose your own country and currency now i simply upload my gerber files and it will produce a preview we have a number of options to customize the product i'll choose the quantity and then i'll leave the rest as default then i'll save this to cart and go straight to the checkout we can choose the postage option to decrease the cost but i want this very quickly so i'm going to order through dhl express then we just submit our order and pay and that's it simple done a few days later a circuit board arrives in the pose from jlc pcb ready for us to build i must say it looks pretty amazing i'm very happy with this service don't forget you can also download a copy of my circuit board for free links for this in the video description down below building the pcb is pretty easy we simply lay out our components and i like to place them in order on this soldering mat i'm also using a holder just to make it a bit easier to work with then we insert the components and we start to solder them one at a time just bend the legs slightly to hold them in place as you solder the components in place just inspect the solder joints to make sure it's okay and then you can trim the leads and then after a few minutes we will end up with our completed circuit board which is ready for testing to test the circuit board i have connected a 9 volt battery to the supply and the multimeter reads 5 volts on the outlet if i reverse the battery we see zero volts on the multimeter so the diode is protecting our circuit i'm happy with this so i place a small load on it and it works great now for the real test i connect a usb port on the outlet and i plug in a cheap phone we can see the 9 volt battery is now charging the device using a usb tester we can see it is supplying 4.6 volts and drawing a current of 0.26 amps so it is working perfectly okay that's it for this video but to continue learning about electrical and electronics engineering then check out one of the videos on screen now and i'll catch you there for the next lesson don't forget to follow us on facebook twitter instagram 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Channel: The Engineering Mindset

Views: 2,968,566

Keywords: voltage regulator, 7805, electronics, 7805 ic, 12v to 5v, lm7805, schottky diode, diode, capacitors, how to convert 12v to 5v, semiconductor, electronic engineering, 5v, pcb, pcb design, altium designer, 12v to 5v converter, voltage regulator ic, pcb design software, electronics engineering, electronics projects, pcb layout, linear voltage regulator, electronics tutorial, altium, jlcpcb, 5v to 12v, pcb design altium, engineering mindset, 7809, pcb design course, electrical engineering

Id: d-j0onzzuNQ

Length: 16min 1sec (961 seconds)

Published: Tue Feb 02 2021