Hello,
i'm designing a powe rsupply ripple/disturbance detector and i was thinking that the best way would be to AC couple the DC signal, then through a precision rectifier and a peak-hold(or Rc smooth filter) take that readout as the absolute ripple level present.
I'm probably going to encounter ~100mV and less ~100kHz signals, i'd also like to be able to detect large spikes and dips(i don't know if i'll be able to use the same circuit, maybe a window comparator will be better suited for that).
Searching the web and TI site i've encountered several examples using precision opamps, single supply/split supply ones, simple comparators versions, etc.
I've simulated all of them but can't quite find what i need, either they don't work as expected or fall under high frequency.
Do i need a precision rectifier at all?, shouldn't a peak-detector alone be enough?, for instance: http://www.discovercircuits.com/PDF-FILES/peakdet1.pdf i've built it but doesn't works well above 500mVpp, it doubles the output above that value (i.e. 1Vpp makes a 2V DC output and i can't figure out why).
Also, ripple won't necessarily be simmetric, and that peak-detector is listed as only following positive peaks (hence back to the precision rectifier one). Is there a simple way to build a high freq precision absolute peak detector?
