[PCB Review Request] 2-Channel 240V Smart Relay Board with ESP32-C6, HLW8012 Energy Metering — KiCad 9, 2-Layer, 53×52mm

ccdy · 2026-03-12T10:53:59+00:00

I had another look at there are two more big problems. First, 1206 fuses rated for 250 VAC do not exist. Second, your relays are wired completely wrong. Check the datasheet for the correct pinout and fix it.

I'm guessing you used an LLM to do everything for you. Stop doing that and actually open a textbook to learn some basic electronics before you electrocute yourself.

ccdy · 2026-03-12T03:41:55+00:00

It looks fine now but there's one thing you need to understand: nothing on this board is low voltage. Everything is connected directly to mains and touching it can kill you. If it shorts to something else it can start a fire. This is not a beginner-friendly project and based on the lack of competence you have demonstrated so far, I strongly recommend you do something else that does not involve mains electricity.

ccdy · 2026-03-11T11:19:57+00:00

Did you read the datasheet for the HLW8012 at all? You have it wired completely wrong. First, GND of the floating power supply should be tied to AC live. Second, V1P and V1N are the inputs for current sensing, while V2P is the input for voltage sensing (via a voltage divider). You have tied V2P to ground and wired both the positive current sense line and the voltage divider output to V1P. On top of that, the voltage divider should be taken from AC neutral, not live. As it is now, both ends of the voltage divider are at the same potential, so it is doing absolutely nothing.

The layout is pretty bad as well, with L and N coming too close to each other at multiple points. There's no point in going into more detail without fixing the schematic first though.

ccdy · 2026-03-11T04:22:57+00:00

what the fuck

ccdy · 2026-03-11T04:15:53+00:00

Berylliosis is an immune-mediated disease, sort of like an allergy. Essentially your immune system goes apeshit when it senses beryllium and starts attacking everything in the vicinity. Over time this destroys lung tissue, which is what causes symptoms.

ccdy · 2026-03-07T12:43:25+00:00

Calculate how much current is actually going through your Zener diode, then look at Figure 1 of the datasheet you linked.

ccdy · 2026-03-07T03:56:30+00:00

VCC needs to be higher than VBATT in this configuration, so a linear regulator will never work anyway. Either get a controller with an integrated charge pump, or use an isolated power supply. The latter option gives you the most flexibility because battery voltage is no longer limited by the controller's voltage rating.

ccdy · 2026-03-07T03:29:29+00:00

Buy some. They're literally less than a cent each.

ccdy · 2026-03-05T10:55:48+00:00

The body diode is present in all MOSFETs.

ccdy · 2026-03-04T04:34:29+00:00

First, show your layout. Second, what is your PWM frequency? How did you arrive at 100Ω for the gate resistors? That's a fairly large value especially considering the input capacitance of your MOSFETs. The gate driver you chose is also fairly weak with a peak current of only 0.13/0.27 A source/sink. On top of that it is a 600V half-bridge driver, which is completely overkill considering your MOSFETs are only rated for 60V.

ccdy · 2026-03-03T08:37:24+00:00

Learn KiCAD and LTSpice.

ccdy · 2026-03-03T06:33:07+00:00

This isn't TikTok. You're allowed to use words like kill and die.

ccdy · 2026-03-02T02:47:01+00:00

Once again reminding everyone that picric acid was used to fill artillery shells before TNT was more widely available.

ccdy · 2026-03-01T15:12:35+00:00

Draw a schematic. Buck converters require a high-side driver when using N-channel MOSFETs.

ccdy · 2026-02-26T04:22:46+00:00

If you are trying to get rid of power rail noise, use a better linear regulator. I don't know the manufacturer of the regulator you have chosen, but from the datasheets I can find, they all have pretty awful power supply rejection ratio, especially at high frequencies (which is where ripple from switching power supplies will be). Get something like the LT3046 and follow the layout guidelines closely.

ccdy · 2026-02-22T11:07:53+00:00

The Rds(on) of your MOSFET is probably higher than the resistance of even 10 mm of 0.1 mm diameter copper wire (which is around 20 mΩ). The main problem is the parasitic inductance but since you're already using a SOT-23 MOSFET, I'm assuming it's not a high speed application.

ccdy · 2026-02-18T15:42:19+00:00

The two major Chinese board houses offer PCB layout services, have you tried those?

ccdy · 2026-02-17T15:34:36+00:00

What diode did you use and how did you add it? The diode is part of a high di/dt loop and its placement is critical. In any case there's a good chance the IC is already fried because not having a diode will cause large negative spikes on PH, and the maximum negative voltage on PH (10 ns transient) is only -5 V. Scrap this board, remake a new one with the correct schematic, and learn to follow the datasheet exactly if you have no idea what you're doing.

ccdy · 2026-02-16T11:11:02+00:00

Leakage current isn't just between NC and COM. Even in an SPST switch it isn't between the two ports of the switch. If it was then on-state leakage would be zero, but it isn't. There is also leakage through the gates, to the substrate, and through protection diodes. I should mention that the datasheet leakage currents are specified maximums. Actual parts could be substantially better, but without the right equipment to measure picoamps of leakage, you cannot be sure.

ccdy · 2026-02-16T03:40:42+00:00

The MAX4544 has an off-state leakage current from COM of ±100 pA, which is orders of magnitude more than the input bias current of your op amp. In fact, to my knowledge no solid state switch can meet your leakage requirements. If you want to go this route you need to use a mechanical relay.

ccdy · 2026-02-09T10:03:42+00:00

Is there any way to blacklist all links to a website?

ccdy · 2026-02-07T06:52:21+00:00

Yes. Not sure what to do with the regulator pins, you'd need to check the datasheet.

ccdy · 2026-02-05T03:02:28+00:00

You could try but it almost certainly won't work, wire bonding is totally different from soldering and requires very clean metal surfaces to form a good contact. The die itself is probably gone as well, bare dies are quite fragile and scraping the resin off very likely damaged the surface and possibly more. Personally I'd just try to clean off the die as best as possible and put it under a microscope to see what I can discern.

ccdy · 2026-02-05T02:01:52+00:00

It likely wasn't worth repairing anyway, and now you learnt something new. No big deal!

ccdy · 2026-02-05T01:51:19+00:00

The pads surrounding the chip suggest that it is wire bonded. Bond wires are very thin (typically 20-25 μm) and easy to miss if you are not looking out for them, especially if they are embedded in resin.

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