My apologies, gentlemen, when I replied I managed to enter the wrong multiplier for capacitors, it should have been 33nF, not 33pF. It's pretty likely that being off by three orders of magnitude had to do with Grumpy-Mike's question.
(Sorry! I'll blame our recent third kid for that malfunction.)
See p. 22-25 of the datasheet re the analog inputs discussion. That's also where Analog shows off it's +/- 0.5V input range for the ADC inside the ADE7753.
The voltage source is a nominal 230VACRMS
input and 6VACRMS
output transformer but the unloaded output is 9.2VACRMS
per the spec sheet. Since this transformer is rated for 230VACRMS
, I presume I can also run it at 115VACRMS
, right? The secondary voltage would then be about 4.5 VACRMS
Here is a drawing of what I think dc42 thought up for me. Could you confirm that I got the architecture right?
The drop-down resistors were chosen BTW to accomodate a 1.41 conversion from RMS to P-P as well as a 25% safety factor. (i.e. the ADE7753 will be able to read input voltages up to about 290VACRMS
being applied to the primary side of the transformer.
The chip itself is OK with inputs as high as 6V without sustaining damage, well in excess of what I expect the transformer to ever survive. The transformer is on a circuit with a fuse and a MOV, hopefully that combination will kill any excesses before they can damage either the switchmode power supply or the transformer.
Thanks again for all the help.