Hello experts,

I've been trying to build a small home automation project using ESP32, PubSub client and an MQTT broker on Android. Rest all is fine, but I was trying NOT to use a relay for controlling the appliances. While considering Solid State Relays, I came across ACST1635 from ST Microelectronics. Looks to be a great component since it can handle upto 16A AC load and can be directly controlled using a uC. All that in a small TO220 package.

My trouble is that, I'm unable to understand the design correctly from the datasheet (please excuse my hobbyist electronics skills). Of what I could see, the "COM" terminal is common to the DC GND of the uC board, and also to the Line Neutral. But I'm not 100% sure if that is how the setup is. And if that is the setup, wouldn't it be risky to have the Line neutral connected directly to the uC board GND? Is there a better way to isolate both DC GND and Line Neutral? I wonder if there is some sort of short circuit or leakage on the AC side, it might enter the uC board and blow it up.

Would someone be able to help me with better understanding how the design is, whether my schematic is correct, and what best to do to ensure safety?

I see that there is another option of SSR-25A as well which is electronically isolated, but that appeared to be a bulky one, which I was trying to avoid.

Thankyou in advance.

Regards,
Deepak

 

Digging a little deeper, I came across this document:

AC Switches ST Micro

I think I had my schematic wrong. Updated schematic is attached here.

My queries still are the same: About the general correctness of the schematic, connecting line directly to the DC supply for the uC board and the safety/security around it.

Thanks
Deepak

 

I also found an evaluation board schematic from ST which uses the same ACS switch (ACST10 instead of ACST16).
AC Switch Evaluation Board

Unfortunately, this is also not bringing clarity in my head about the design But might be it does to some other higher/greater soul out there?

Regards,
Deepak

 

Any kind soul willing to help?