Hello there, I've been try to learn how sigma-delta ADC works, I've been through the block diagram mostly and tried simulating one myself by following this video lecture from "The signal path" channel, the wiring is right as it shows in the circuit diagram( from timeframe 34:30 ) and it also follows the other block diagrams i came across, I have tried using the D flip flop as an 1 bit DAC with its 2 values set between +/- 5v, as said in the video, why doesn't this simulation work as intended, am i missing something here with reference voltages?, I have included the simulation file below. Please help me resort this issue, Thank you.

 

Hi CR,
Where did you find the 'Comp' model?
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Hi CR,
Where did you find the 'Comp' model?
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I'm using the component library provided by Bordodynov on his webpage named "Additional library for ltspice" searched the keyword "Comparator", exported the first one that came up.

 

Hi CR,
When using that comp model, I get this error message, which is related to that comp model.
Do you get the same error?

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BTW: I do have the bordodynov ZZZ folder

 

hi, CT,
With the comp removed, the two OPA stages work as expected.
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Hi,
Using a buffer set for +/-5v I get this result.
Do you have the complete circuit you could post?
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Hi,
Using a buffer set for +/-5v I get this result.
Do you have the complete circuit you could post?
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View attachment 322974

I have this circuit from the video i mentioned earlier in my post. The circuit should output an PWM modulated waveform at Q point.

 

View attachment 322976

Can i get the new simulation file, What changes did you make in the circuit to make it work. thank you.

 

Can i get the new simulation file, What changes did you make in the circuit to make it work. thank you.

Here you have it: