5 big points that cannot be ignored in power supply design

- Oct 20, 2018-

In power supply design, PCB design is only a part:

1. The first is to have a reasonable trend:

Such as input/output, ac/dc, strong/weak signal, high/low frequency, high/low pressure....Their movements should be linear (or separate) and not blend with each other.The aim is to prevent mutual interference.The best alignment is a straight line, but generally not easy to achieve, the most unfavorable alignment is circular, fortunately isolation can be set to bring improvement.For dc, small signal, low voltage PCB design requirements can be lower.So "reasonable" is relative.

Choose a destination: the destination is often the most important.

Its importance can be seen by the number of engineers and technicians who have written about it.In general, common ground is required, for example: several ground lines of forward amplifier should converge before connecting to the main line, etc..In reality, it is difficult to fully do because of various restrictions, but you should try to follow them.The problem is quite flexible in practice.Everyone has their own set of solutions.It is easy to understand if you can explain specific circuit boards.

5 big points that cannot be ignored in power supply design

3. Reasonably arrange power filter/decoupling capacitance.

In general, only a few power filter/decoupling capacitors are shown in the schematic diagram, but it is not indicated where they should be connected.In fact, these capacitors are set for switching devices (gate circuits) or other components that need to be filtered/decoupled, and these capacitors should be arranged as close as possible to these components as far away from them as possible.Interestingly, when the power filter/decoupling capacitance is properly disposed, the problem of the connection location is less obvious.

4. The lines are exquisite, the line diameter is required, and the hole size of the buried hole is appropriate.

If you can make wide lines, never thin them.High pressure and high frequency line should slide, no sharp chamfer, no right Angle.The ground should be as wide as possible, preferably with a large area of copper coating, which is a considerable improvement in the docking site.The size of the weld pad or overwire hole is too small, or the size of the weld pad and drill hole are not suitable.The former is disadvantageous to artificial drilling and the latter to numerical control drilling.It is easy to drill the pad into "c" shape, then drill off the pad.The wire is too thin, and the large area of the unwired area is not set with copper, easy to cause corrosion uneven.That is, when the corrosion of the unwired area is finished, the thin wire is likely to be overcorroded, or not broken, or completely broken.Therefore, the function of setting copper coating is not only to increase ground area and anti-interference.

5. Number of holes, solder joints, wire density.

Although some problems occur in post-production, they are caused by PCB design. They are: too many holes in the lead wire, and any careless mistake in copper sinking process may lead to hidden dangers.Therefore, in the design should be minimized through holes.Parallel lines are so dense that they can easily be joined together.Therefore, the line density should be determined according to the level of the welding process.The distance of welding spot is too small, which is not good for manual welding.Otherwise there will be hidden dangers.