Regulator and Other Heating Components Cooling Techniques with EasyEDA x JLCPCB
What You Will Learn From This Article
There may be some components that generate high heat, such as the regulator, on the PCB. In order to prevent these components from being damaged, I am explaining PCB cooling techniques for you via EasyEDA of JLCPCB.
Especially if your circuit has to be fed with 12V and you are doing things that will draw a little more current with a 5V regulator, you will notice that your regulator gets very hot. You want to prefer an SMD regulator in your circuit. No problem. If you are not going to draw more than 400mA current, I am sharing a few circuit tricks for you.
In this article, I will not go into technical calculations for the sake of appealing to everyone. I will just tell you the methods. If you really want an article that includes technical calculations, you can let the JLCPCB team know. I will also prepare that article for you.
1. A Regulator-Specific Tactic
First of all, we need to know that voltage regulators stabilize the voltage by converting excess energy into heat.
For example, let's say we have a regulator that reduces the 12V input to 5V. Let's say our circuit draws 500mA current. The regulator will need a voltage drop of 12V-5V=7V. Since the current flowing into the circuit through the regulator will be 500mA, 7V × 500mA=3.5W excess power will be converted into heat by the regulator. This creates a very high heat and requires a large heatsink aluminum plate or fan. Now JLCPCB will have a few tricks for you.
Did anything catch your attention? Since we cannot change the current drawn by the circuit, the greater the difference between the supply voltage of the regulator and the output voltage, the higher the power to be converted into heat will be. In that case, if we reduce the voltage difference to the minimum level before the regulator, the regulator will not overheat.
We can use diode for this. Generally, the supply voltage of 5V regulators should be minimum 7.5V. You can check this from the regulator's datasheet. We can reduce the 12V voltage to 7.8V by placing 6 silicon diodes (holding 0.7V voltage on the silicon diode) between the 12V voltage and the Vin pin of the regulator. There are two issues that we should pay particular attention to here. First, it is necessary to choose a good diode so that the diodes do not overheat or burn when they carry this current. The second is that we did not accidentally choose a low voltage holding germanium diode. Because these diodes will not hold 0.7V voltage, the calculations will be wrong. If your circuit draws too much current and the silicon diodes holding 0.7V cannot withstand the current, you can spread the heat over more diodes by using 15 germanium diodes holding 0.3V voltage instead.
2. Using the PCB as a Heatsink
Placing heatsinks on components often means extra workload and extra cost. You can use the PCB as a heatsink instead. In order to apply this method, you should pay attention to the package when choosing the component. It is very useful to have a heatsink surface that is in contact with the PCB surface as in the picture below. I will discuss this issue in more detail in Chapter 4.
A component with a cooling surface
You can find these components in JLCPCB's Assembly Parts Library. If you create a large copper area on the heatsink surface of the component as you can see in the picture below, the heat generated will spread over the PCB. So the component will cool faster.
A regulator cooling by PCB copper area
Let's look at how we created this copper field in EasyEDA of JLCPCB. As seen in the picture below, we first click on the option to create the copper field. Then, from the drop-down menu, we select Net to which the heatsink pin of the component is connected. (You can find which pin the cooler surface is connected to from the component's datasheet.)
We draw the boundaries of the cooling copper area that will form around the component. (Avoid long thin drawings. Try to draw a border as close to the square as possible. Take care not to have different components within the borders you have drawn. A path passing through the cooler area may cause the cooler area to not work. Below you can see the incorrect and correctly applied cooler areas.)
Examples of correct / incorrect cooling with PCB copper area
Great. We created a cooling area for the component. Now let's make this area more effective with a simple trick. We create the same area that we have determined at the back of the circuit. Then, we add plenty of vias (jumping holes) to this area so that the heat can pass well behind the circuit. Of course EasyEDA will do this for us automatically.
Let's take a step-by-step look at how this is done with EasyEDA of JLCPCB.
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Step 1
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Step 2
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Step 3
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Step 4
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Step 5
Creating a double-layer heatsink copper area with EasyEDA of JLCPCB / Finish
We now have a good cooler area. We can use the same methods for the pads of the diodes.
Cooling of voltage step-down diodes with wide copper paths in EasyEDA of JLCPCB.
3. Component Selection
In order for our cooler area to work well, the component we will choose should have plenty of contact with this area. That's why choosing the right component is important. You can easily meet your component needs from the JLCPCB Assembly Parts Library. You can also see their prices and compare them with equivalent products and add them to your circuit instantly with the product code. You can see the stock status and create your order with one click, including assembly, without any extra action. From the picture below, you can see the regulators that we should and should not choose for cooling from the Assembly Parts Library of JLCPCB.
JLCPCB Assembly Parts Library / A component that does not have a heatsink surface
JLCPCB Assembly Parts Library / A component with a heatsink surface
JLCPCB Assembly Parts Library / A component with a heatsink surface
Finally, you can see a regulator circuit prepared with the techniques in this article below.
A regulator circuit with a heatsink copper area designed in EasyEDA of JLCPCB using the techniques in the article
Stay tuned for more technical information and tricks.
Note: The methods described in this article make the heated components in your circuit less warm, but since this article does not include technical calculations, the methods described here are not guaranteed to protect your circuit against heat.
JLCPCB Part-Time Engineer / Berkay EVREN