Hi Guys,
please find attached LT Spice find.
I wanted to get triangular wave from 5V peak to peak (-2.5V to +2.5V) rectangular input signal with 50us high and low pulse
As per my theoretical analysis triangular wave should start from 0V to -2.5V and -2.5 to 0V , (Negative integrator).

Could anybody help me to get the results.

Regards

 

Try this :-

 

Try this :-

Hi,

Thanks for your reply.
Why do you use R3, C2, R4 ?
If simple integrator circuit is as per below.

I still not understand the use of those components.

 

Try this :-

In addition,

If C1 = 10n
R1 = 10K
Ton = Toff = 100us

DeltaVout = 5V

But in your simulation it is coming 2.5V only.

Please clarify my doubts

Thanks again

 

Why do you use R3, C2, R4 ?

They provide a smoothed voltage to bias the opamp inverting input so that the output is in the 0V to -2.5V range that you want. I haven't done the maths.

 

Below is the simulation of your circuit, slightly modified.
I added an input DC block capacitor so that the average input is always 0Vdc, to avoid output offset from that, and lowered the value of R2 to reduce the start-up settling time.

 

I am surprised that the simulation did not use an impossible opamp with no input offset voltage.
I didn't look but maybe because the input transistor in the opamp are bipolar with some input bias current.

 

Below is the simulation of your circuit, slightly modified.
I added an input DC block capacitor so that the average input is always 0Vdc, to avoid output offset from that, and lowered the value of R2 to reduce the start-up settling time.

View attachment 205907

Hi,
Thanks for your support.
I studied in some book as per below and i wanted to do the simulation but i did not see the same results in any of above simulation.
Could anyone please guide me here to get the results as per below.


Thanks in advance !!!

 

Try this sim. I suspect a real-world circuit won't give the same results, because of input bias tolerances and non-rail-to-rail output of the op-amp.

 

Try this sim. I suspect a real-world circuit won't give the same results, because of input bias tolerances and non-rail-to-rail output of the op-amp.

Hi Alec_t,

Thanks for you support,
Yes, it worked as expected.

Thank you very much again !!!