As exciting and difficult as the process of PCB design might be, it’s indeed critical to take all required measures to guarantee appropriate circuit performance, particularly when working with the high power PCB Designs.
As the electronic device sizes continue to shrink, design concerns like thermal management and power supply must be considered. This article offers some reliable principles for the designer to follow when designing a PCB for high power applications.
What is a High-power PCB?
There is no formal description of what makes up the high-power PCB. P=IV defines power, and the high power PCB design could be a circuit with high current or voltage elements. The query is, what is the voltage and current threshold for a printed circuit board to be called “high-power”?
Rather than imposing a tight definition on its characteristics, it is simpler to classify high-power PCBs based on issues that may develop if correct high power PCB design standards are not pursued: electrical shocks and thermal generation.
High power PCB designs in electronics typically conduct current in excess of a few amps. The high-power PCB are the electrical motor drivers that can channel about 30A of electricity inside the circuit. The same is true for the LED driver that could be powering several LEDs arranged in arrays.
High Power PCB Design Considerations
Trace thickness and width
In general, the longer your track, the higher its resistance as well as the heat that gets dissipated. Because the purpose is to reduce power losses, our recommendation would be to keep those traces which conduct large currents as small as possible so as to guarantee high reliability as well as endurance of a circuit. Designers can use the calculations in IPC-2221 standard and the online calculator to appropriately calculate a track’s width, knowing the highest current that can run through it.
This same trace thickness for a normal PCB is roughly 17.5 µm (or 1/2 oz/ft2) mainly for its internal layers then 35 µm (or 1 oz/ft2) mainly for the exterior layers and ground planes.
To decrease track width when using same current, high power PCBs often employ thicker copper. This decreases the amount of space taken up by the PCB traces.
PCB Layout
Before running the very first trace on the high-power circuit, it’s indeed critical to have high-level knowledge of its layout. Also, the layout of the board should be addressed from the beginning of Circuit board development. Determining the power’s path is an important criterion that pertains to every high-power PCB.
The placement as well as amount of electricity flowing via the circuit is crucial factors in determining how much heat the Circuit board must dissipate. The following are the primary aspects that influence the PCB layout:
- power going across the circuit
- The ambient temperature within which the circuit board operates
- the quantity of air movement influencing the board
- the material utilized to manufacture the PCB
- Density of the components populating the board
Placement of the Component
It is critical to initially determine the location on the Circuit board of the high-power components, like power transistors or voltage converters that generate a significant quantity of heat. The high power components shouldn’t be put near the board’s edges, as this produces heat buildup as well as a large increase in temperature. Fully integrated components, like microcontrollers, FPGAs, and processors, should be inserted close to the center of a circuit board to allow for homogeneous heat diffusion over the board thus, as a result, a reduction in temperature.
To prevent the production of hot spots, its power components shouldn’t ever become concentrated within a single region; instead, the linear type design is recommended.
Thermal management
In order to keep every component within acceptable temperature limits, appropriate thermal management becomes required. Never allow its junction temperature to surpass the limit specified in the datasheet of the manufacturer (usually within +125 °C to +175 °C for the silicon-based devices).
That heat created by every component is transported outwards via the package as well as connection pins. Manufacturers of electronic component have created increasingly thermo-compatible packaging in past years. Despite these advancements in packaging, heat dissipation gets more challenging as the integrated circuits’ size shrinks.
Solder Mask
Another method for allowing a trace carry more current is removing its solder mask out of the Circuit board. This reveals the copper material that may be reinforced with extra solders to enhance copper thickness and lower overall resistance present in the PCB’s current-carrying components. This approach allows the PCB traces handle more power and without increasing trace width.
Material selection
Electronic circuits that suit high-power applications necessitate not only efficient design strategies, but the PCB materials that can dissipate the considerable quantity of heat generated by these components. As a result, high power Circuit boards employ materials with minimal losses as well as high-thermal conductivity.
Thermal conductivity, which suggests how successfully heat travels via a material but also can be expressed in form of power watts for every meter of the material as well as per degree Kelvin, can be described as one of the major parameters that influence material selection. Copper, for example, has a thermal conductivity value of 400 W/m/K and can transfer the thermal energy extremely quickly.
Including Safety Features in a High Power PCB Design
A major concern regarding high power PCB designs, as with all other circuits, is its ability to function safely. There are some potential issues which are unique to boards which drive those types of high-powered loads. This same primary danger is heat.
The main danger is heat. Regardless of the quality of design as well as lay out that board, it generates more heat than the standard boards. This ought to be constantly considered when building the housing, as well as external fans/vents should be used.
Overheating is a legitimate concern in the high power PCB design. The risk of a load short-circuiting as well as drawing excessive currents from the regulator or MOSFET is also present. Detect such incidents by including suitable security features in such a design.
When placed near heat-generating components, the temperature sensors will be useful. It sends alerts whenever the Circuit board temperature surpasses a safe level. Place fuses somewhere at high current outputs to ensure short-circuit safety to guarantee that connections are immediately cut off, whenever there is a rise in current above the safe threshold.
More safety features
Short circuits constitute the following potential safety hazards. Because the board has been designed for driving high-power devices, this can source a significant amount of electrical current when shorted. This possibility must be taken into account during the stage of design. The simplest method for dealing with shorts involves having a fuse present on all the outputs as well as the input fuse.
The fuse ratings should always be less than what the wires can handle. Also, they ought to be evaluated for a lower or equal current that the board pours/traces have been designed for. Additionally, it’s a great idea to utilize drivers which have in-built short-circuit protection.
While working on the high power PCB designs, you’ll require a reliable PCB design software. If you’re working with OrCAD, you’ll discover that implementing the above techniques we mentioned is a simple process having the necessary tools at your disposal.
Techniques for Creating a High-Performance PCB Design
Layers should be doubled
One technique I’ve used with several high-powered circuits but haven’t seen much is having the double-layer copper pour as well as stitching them altogether with vias. Such a double module enables twice as much copper to become present within a single area. iFor such a board, we doubled the copper from its terminal into an input fuse onto the main power input.
Make use of copper pours
I always attempt to utilize copper pours with all the power nets, regardless of the board type I’m designing. When working with dedicated high-current designs, all high power nets ought to pour. Also, copper pours boost the copper width that fits on the board significantly.
Recognize the trace width calculators
When designing a circuit board, users must be aware of the least trace width. It’s particularly crucial when working with the high power PCB designs. I have no particular favorite calculator because they should be based on just one IPC-2221 formula. The calculator will be used on 2 major high-current nets on this board.
The initial is the major 30A supply, which runs from the power supply towards the fuse and then branches.
Make use of thermal reliefs
There will always be some disagreement when discussing thermal reliefs throughout high power PCB design. When soldering, thermals are used to prevent heat from wicking to your surrounding copper. They do a good job of it. They have the drawback of having very little copper available for current flow. Also, for the standard PCB, this is usually a small concern, and these thermal advantages far outweighs the disadvantages.
PCB High Power Applications
Electronics are now an indispensable component of our everyday lives. We want electricity for everything, including smartphones and home appliances. The PCBs are electricity’s major factor.
It serves as the foundation for the majority of today’s electronic devices. This adaptability allows PCBs to be used in a wide range of capacities and applications. We’ve discussed some applications in more detail below:
Medical Equipment
All electronics plays an essential part in the medical industry, serving as control, diagnostic, as well as treatment systems. Also, as electronics are becoming more compact and powerful, medical applications for these devices expand, opening up a variety of fresh possibilities.
Circuit boards in the healthcare profession are highly technical in order to comply with the particular constraints of the medical equipment. Medical PCB, which is also known as the HDI PCB, seems to be specialties of high-density interconnect PCB.
Customizable base materials may additionally be manufactured from the medical PCBs, enabling PCBs to be able to flex while in use, which is useful for both exterior and internal medical devices. Also, aside from adhering to strict medical regulations, the suppliers of medical PCB must demonstrate repeatability and dependability. The following are some of the common medical Printed circuit boards:
Monitors: Health and personal care monitors include blood, heart rate, glucose, as well as monitors of blood pressure.
Chemical Equipment: Medical science employs a variety of scientific methods for studying illness as well as testing patient effects. These include photometers, electronic microscopes, as well as compressor and generator control systems, among other things.
Consumer Electronics
Computers, smartphones, and a variety of consumer goods rely on Printed circuit boards to function. As electronics became more prevalent in our everyday products, Circuit boards became an integral component of how we live. Companies are producing smaller laptops and smartphones using a variety of novel technologies that include tiny PCBs having high link volumes.
Circuit boards are utilized in a broad spectrum of consumer products, including computers and laptops. In the twentieth century, computers were used in every aspect of life. PCBs are found in laptop and desktop computers. They act as the foundation for many internal computer components. All of these components are linked directly to a motherboard; this can also be called a PCB.
Industrial Equipment
High power PCB design in our industrial sector must also be extremely powerful and robust enough to withstand harsh conditions found in the industrial installations.
PCBs throughout the industrial sector must also be high-powered as well as robust enough to withstand harsh conditions found in the industrial installations.
Conclusion
This article should have provided some insight on the proper tricks and techniques which could be used with the high-powered circuits. There are so many nuances which you wish to look in whenever you are working on the boards; they aren’t much complicated compared to the standard board designs so far the basic “rules” will be followed. The key points are to keep security in mind always, start with a very solid plan, use much copper as possible, and always check the trace width using a calculator.
