I need a circuit that give in the output a voltage value proporcional to the AC line (120 Vrms). The circuit must provide an output from 0 to 5 Volts, proporcional for an input from the line of 0 to 150 Volts (rms). I'll use this output (0 to 5 Volts) as an input to comparator.
I was thinking of use a transformerless power supply, but maybe the acurracy of the output it's not enough reliable cause of the ripple, and it's dificult to make a good proporcionality respect to the input.
I'm not sure if i'm in the right way. May you give me some advices? By the way, for my application i can't use transformers (yeap, it's more difficult).
Thanks.
I was thinking of use a transformerless power supply, but maybe the acurracy of the output it's not enough reliable cause of the ripple, and it's dificult to make a good proporcionality respect to the input.
I'm not sure if i'm in the right way. May you give me some advices? By the way, for my application i can't use transformers (yeap, it's more difficult).
Thanks.