Problem with fully switching on comparator in a circuit

[groody]

Comparator

Hi!

I'm designing a circuit which has a comparator inside. Currently I'm using a Op-Amp with +5/-5 supply.

The input voltage is between -5 and +5 V. The output voltage should be 0 or 5 V, and I'm currently achieving this through a peak detector (a diode in series with a resistor with a shunt capacitor).

The problem is, I would like to force it to fully switch every time the threshold is crossed, while because of a feedback far from the comparator, once it starts to switch the input voltage goes under the threshold again and the output switches back to the original value (the capacitor discharges through the resistor).

The logic afterwards fails to detect the transition because of a setup/hold violation.

Any idea?

 

[tshah]

Re: Comparator

Hi Groody,

Earlier I designed a project using opamp and for designing a comparator I used differential type-3 amplifier. I don't know what topology you are using. I designed it with a very high gain.

Thanks