Hello and thanks in advance for your help.

I started playing with electronics about 5 years ago when I got my first Alexa. Purchased some Wemos D1 Minis (Esp8266's modules) and some cheap USB power supplies. Quickly realized that no all USB power supplies were equal, as the cheap ones would make the D1 Mini act up, especially when it came to using touch sensors. As I got more experiance I stopped buying USB power supplies and instead got some real 5v power supplies, mainly the HiLink HLK-PM01 (5v .6A). I never looked at its datasheet or anything. I just soldered some wires to the pins, connected the AC lines to the AC, and connected my 5v devices directly to the 5v output. I have about 10 devices currently set up like this for over 3 years and haven't had any issues. I connected most of my modules with cat5 cables, and ended up with the nest of wires, but all the devices work as expected.

About 3 months ago I realized I could easily design my own pcb boards and have them done and shipped from China very cheap. Now that I am designing my own pcb's I am actually taking the time to look at the datasheets. I am now looking to start working with HiLinks HLK-10M05 wich is a 5v 3A ac to dc power supply.

The datasheet can be seen here https://www.rhydolabz.com/documents/30/HLK-10M05 Datasheet.pdf



I now have a few questions. First is the classic "if it ain't broken don't fix it". I have used over 10 similar power supplies for the last 3 years without any of the capacitors, varistor, etc., and didn't have an issue. In fact only 3 or 4 have a fuse on the Live wire, the rest are connected straight to the mains. They have gone through many power outages, some caused by thunder and so far ZERO issues.

The data sheet mentions "Fuse and varistor are basic protective circuits." I had already implemented a fuse on my PCB design, and was able to locate correct varistor on the LCSC site (I design using EasyEDA) so plan to use them.

Now the C1, L1 and C2 are the ones I haven't figured out yet.

The datasheet states "If you need to pass the authentication, the Anchorage capacitance and common-mode inductance must not be omitted." I have no idea what they mean by "pass the authentication". Since I don't know what it means I am assuming I am not passing authentication, so I could be ok not using them?



What would be the downfall of not using the safety capacitance and the common-mode inductance? (If I do have to include them I would have to find a bigger box and re design my board since with my current setup I am MAXED out on space)

Assuming it is very important that I use those parts, how would I find them? Well as I was typing this post I did manage to find the Safety Capacitor in LCSC. I wasn't finding anything that was .1uF but after quick google search found out .1uf is 100nF. However the Common-mode inductance I seem to be hitting a dead end.

When I go to https://www.lcsc.com/products/Inductors-Coils-Chokes_316.html I don't know which section I should look in.

 

So after digging around for a bit I finally found all the parts needed in LCSC. Turns out the common-mode inductance is not an inductor but a filter. On the filter section of LCSC I was able to find them.

Now just need to know if it necessary or I can do away without them.

 

A common mode choke most definitely is an inductor. It is best though of as a pair of coupled inductors each in series with a non-coupled inductor, as it is deliberately made to be not very well coupled.
A filter is the combination of inductance and capacitance. An inductor is not a filter on its own.

The "authentication" would be the relevant EMC standards, the titles of which vary from country to country, but the substance varies rather less, so are likely to be the same as EN55014, EN55015, EN61000.

"If you need to pass the authentication, the Anchorage capacitance and common-mode inductance must not be omitted."

is a de facto admission that the power supply on its own would fail EMC standards, in which case you need external filtering.

Safety regulations would require you to prove that there is no hazard if a component failed in your the power supply, especially in the cases where you have no fuse. The fact that you have made 7 and no-one has been killed an no house fires were started would not be a very good defence.

The subtle point is within the box which you label "power module". There is almost certainly a capacitor which couples the mains voltage to the negative output, it will be about 2.2nF so the current from the mains will be limited to 150μA.
A problem occurs if you use several of these power supplies, and interconnections end up connecting the V- terminals together. Then the mains currents add up. After about 5, it would fail safety regulations and people would complain that they are getting shocks (especially if you are using them on touch switches).

I would therefore recommend connecting the power supply V- to mains earth.
You could also connect Class-Y capacitors between live and earth and between neutral and earth to improve the interference filtering.

If you haven't tested the power supply insulation to check it meets the standards, the authorities would not look favourably on that either.

 

The subtle point is within the box which you label "power module". There is almost certainly a capacitor which couples the mains voltage to the negative output, it will be about 2.2nF so the current from the mains will be limited to 150μA.
A problem occurs if you use several of these power supplies, and interconnections end up connecting the V- terminals together. Then the mains currents add up. After about 5, it would fail safety regulations and people would complain that they are getting shocks (especially if you are using them on touch switches).

Thank you so much for detailed explanation. For what it is worth if I was still living in USA I wouldn't play with electronics as I do here in Mexico. Homes here are made out of center blocks and cement, so worst case scenario I burn the wiring but the house itself would never catch fire.

I do have a question regarding "A problem occurs if you use several of these power supplies, and interconnections end up connecting the V- terminals together. " You mean if I use many power supplies together or do you mean if I use many power supplies in the same home?

Also would like to clarify, I was under impression that the common-mode inductor was to reduce noise but does nothing for "safety". Am I wrong? Can too much "noise" be dangerous or does it just affect how some signals are sent/received?

 

I do have a question regarding "A problem occurs if you use several of these power supplies, and interconnections end up connecting the V- terminals together. " You mean if I use many power supplies together or do you mean if I use many power supplies in the same home?

The salient point is "connecting the V- terminals together", which happens if there are interconnecting cables between them.

Also would like to clarify, I was under impression that the common-mode inductor was to reduce noise but does nothing for "safety". Am I wrong? Can too much "noise" be dangerous or does it just affect how some signals are sent/received?

There is a tenuous connection between filtering and safety: Excessive interference can cause safety equipment to malfunction, if it interferes with data transmission within or between devices.

 

Setting aside 1000s of pages of safety comments, IMO the L-N or L-L spacing is less important than the L-+Vo. If L-N shorts out, you pop a breaker. If you short L to someone's headphones, there is a real chance of death.

In your filter, the lead spacing for Varistor or L1 might be too small, so I add a 1mm slot between the legs (sometimes). Some of my boards will be in an environment where water might pool on the PCB. You probably don't need this, but it is an option,

For the Line to +Vo (-Vo) spacing, keep it wide! You can always use slots to help.

In your layout you can make strange pads to help with spacing. Normally you would have a round pad the C1. But you can make a "D" shaped pad where there is almost no copper in one direction. Be creative.

The power line (blue) has noise you don't want on your project.
The Power Module makes noise, and you project probably makes noise that you do not want on the power line.
The filter/inductor/transformer isolates high frequency noise. Everything in blue and those in green need to not talk to each other. Any capacitance where the red arrows are is bad. Don't even let the blue and green traces cross on opposite sides of the PCB. (Not safety, but nose filtering.)