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ADE7753 Voltage Attenuation with non-isolated supply

Question asked by IanW on Oct 31, 2013
Latest reply on Jun 1, 2016 by dlath

Hi,

 

I have a design using the ADE7753, and having a problem with the Voltage Inputs (V2P, V2P) and the attenuation network.

 

The attenuation network is the same as on the ADE7753EB. The V2N input is connected to AGND (through a 1K resistor), but not connected to NEUTRAL (i,e, in ADE7753EB figure 6 there is no connection between SK1.1 and NEUTRAL).

 

This connection is not present because the power supply for the metering chip is a non-isolated switcher, with a full-bridge rectified input.  This results is system DGND (and thus AGND) being at a different potential to NEUTRAL.

 

Is there a simple way to reconfigure the attenuation network to give the appropriate input to the meter, yet overcome the inability to connect AGND to NEUTRAL?

 

Any help would be greatly appreciated.

 

Thank you,

 

Ian

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