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Component values are unknown

wounder

Jun 15, 2019
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I have a circuit consisting of ESP8266,STM and a single relay.

For supplying power to these IC I need an SMPS circuit.

I got a non-isolated buck converter (using VIPER06Xs) as shown but the component values are unknown.

Could you please tell the suitable component values needed for this circuit? I chose this converter because the PCB that I will be planning is small in size.

Voltage needed for ic--

  • ESP = 3.3 V
  • STM = 3.3 V
  • RELAY = 5 V
https://www.st.com/resource/en/datasheet/viper06.pdf
 

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Bluejets

Oct 5, 2014
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I think you need to supply a bit more info about the project as a whole.
 

wounder

Jun 15, 2019
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I think you need to supply a bit more info about the project as a whole.
project simply a smart socket.
figure below gives much details
 

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Audioguru

Sep 24, 2016
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The circuit posted has its ground connected directly to mains electricity so it presents a serious shock hazard and this thread should be closed with the warning.
 

Harald Kapp

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The circuit posted has its ground connected directly to mains electricity so it presents a serious shock hazard and this thread should be closed with the warning.
Considering that the SMPS module is non-isolated you are completely right.

@wounder : I suggest you use an isolated SMPS for safety reasons. The green area then is safe under this condition. You should not trade safety for size!
upload_2019-6-22_19-9-28.png

I think you need to supply a bit more info about the project as a whole.
You need to know the current drawn by the relay (5 V is insufficient information). The use this our resource for selecting componnet values.
 

wounder

Jun 15, 2019
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The circuit posted has its ground connected directly to mains electricity so it presents a serious shock hazard and this thread should be closed with the warning.
Considering that the SMPS module is non-isolated you are completely right.

@wounder : I suggest you use an isolated SMPS for safety reasons. The green area then is safe under this condition. You should not trade safety for size!
View attachment 45554


You need to know the current drawn by the relay (5 V is insufficient information). The use this our resource for selecting componnet values.
Could you please provide other SMPS circuit rated(min of output 500mA)
 

Martaine2005

May 12, 2015
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In post #3, how is this circuit connected to ground?. It looks completely fine to me. Am I missing something?.

Martin
 

davenn

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In post #3, how is this circuit connected to ground?. It looks completely fine to me. Am I missing something?.

Martin


agreed

Considering that the SMPS module is non-isolated you are completely right.

huh ??
and how did you determine that the off the shelf charger he is using is non-isolated ?

Yes, his first cct showed a non-isolated converter … BAD
but the cct in post #3 doesn't and as long as @wounder uses a smps as in post #3 he will be good to go

I'm about ready to clean up this thread stating with AG's screwball post
I think AG and Harald have both missed something

But I await some responses first
 
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Audioguru

Sep 24, 2016
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The Viper 06 Buck Converter shown in post #1 has its ground connected directly to one side of the electricity with no isolation.
 

davenn

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The Viper 06 Buck Converter shown in post #1 has its ground connected directly to one side of the electricity with no isolation.


yes, as I said, that one was bad, but his update in post #3 was good :)
 
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