Switch Cap integrator trouble...

[kart339]

Hi everyone,
I have a switch cap integrator in my design. It works fine when I test it by itself and also when it's placed in the actual app with no load before it. But as soon as I place a comparator (ideal) before it, the ramp changes to a square waveform. Anyone knows why this happens and how to fix it?
Thanks in advance!
Kart

 

[bastos4321]

Please provide a schematic of your circuit so that we can help.

Bastos

 

[kart339]

I dont have a schematic as it's a spice netlist file but here is a diagram of what i am trying to implement. I am using a 30 ns switching freq for my switches. Also, I am seeing spikes in my ramp output. Is there any way around this?

 

[bastos4321]

Are you using a nonoverlap phase generator to control the switches. The spikes in the output are due to charge injection and are commom when there is a phase change. Apart of this your circuit seams normal and should work ok.

Bastos