Hi All , I am looking for the solution for my project .I just bought the evaluation power monitoring board from ST its name was EVALSTPM34 and I having the problem on the DC power for the microprocessor on AC line .The 1st picture is my basic connection and the 2nd picture is the schematic for EVALSTPM34 board.

Problem = turn on the AC and DC Isolated power supply ,the isolated DC supply explode while the EVALSTPM34 did not working the bulb remain OFF
Schematic[Metrology Circuit]= I wondering why the neutral and DC ground is connected (refer connector J8 , i measured the resistance neutral-ground is <0.7ohm)

Step taken=
1.testing putting different value of resistor(1M,2.2M,1.5K,600ohm) between Neutral-Ground ,DC part seems working while the AC remain OFF
2.did contact with ST support but they did not answer my question.

Hope You guys can help me to find the best solution for my project thank you

 

Incomplete post.

 

The l1 connection you have your bulb going to is line voltage input, not a switched output, hence its requirement to have a common connection between the AC line common and the DC common.

A quick read over the STPM33 IC's data sheet would have told you that.

http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.DM00111861.pdf

 

It looks like your L1 connection point is set up as a voltage input, not a switched output hence the need for it to share a common connection between the AC line common and the DC common.

yeah i agree with you tcmtech , but how about the board connection neutral is directly connected with DC ground ? even in schematic they said 1.5kohm between Neutral-Ground but I could n`t find any existing of this thing.

 

Unfortunately, it has to have the two common lines connected so that the two circuits can work together inside the IC.

If the power supplies are blowing up something is wired wrong or they do not have true isolation from their AC power input side to the three DC power output side and the AC line power is feeding through them into a shorted circuit being their DC common is sharing a connection with the AC common.

Does the circuit work on battery power?

 

The l1 connection you have your bulb going to is line voltage input, not a switched output, hence its requirement to have a common connection between the AC line common and the DC common.

A quick read over the STPM33 IC's data sheet would have told you that.

http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.DM00111861.pdf

basically the board connection that I make almost the same like User Manual UM1748 [ http://www.st.com/resource/en/user_manual/dm00113794.pdf ]

wait ...I think my bulb is currently in series connection between L1 and AC source ...but I don't think it can solve the problem.
Ok I going to test with the battery supply ..but what if the battery supply also explode ?

 

Ok I going to test with the battery supply ..but what if the battery supply also explode ?

The battery supply is a totally isolated non AC line connected power source. If it explodes you have a whole lot of other problems to deal with.

 

I just found the solution I just re-check and identified my wire connection is not really correct, so I follow the connection from the previous posted diagram and re-connect all of the wire and walllllaah is working

thanks a lot tcmtech for your guide