triangle wave generator using 2 lm324 and single supply operation

Thread Starter

denison

Joined Oct 13, 2018
55
Has anybody got the formulas for building a dual op amp triangle wave generator using a single power supply?
 

crutschow

Joined Mar 14, 2008
23,309
Has anybody got the formulas for building a dual op amp triangle wave generator using a single power supply?
No, but I can post a circuit tomorrow.
It's just a comparator driving an integrator in a feedback loop.
 

danadak

Joined Mar 10, 2018
3,573
Some questions -

1) Frequency range ?
2) You need to sweep it over a range ?
3) Other outputs needed, like sine, saw, square ?
4) Output V ?
5) Load to drive ?
6) Accuracy ?
7) How do you want to set freq and amplitude ?

Regards, Dana.
 

Thread Starter

denison

Joined Oct 13, 2018
55
thanks for the schematic bertus. My circuit is very similar but the triangle output is not symmetrical. The slope of one side takes longer than the other side.
For the frequency you show Rc . there is no Rc in the schematic. What should this be?
You show a 100k resistance between + and - terminal of the comparator. My circuit does not have this. Is this a correction for the output of the lm324 not being rail to rail?
My power supply is 8v. I started out with 4v reference but could not get a large triangle wave. I changed the ref to 3.48 using a Ltspice simulation. My triangle wave is approx. 1v low and 6.38v high .The saturation voltage for the lm324 in Lt is 6.5v.
Another formula is necessary to get the upper threshold and lower threshold of the triangle wave. My bible is "operational amplifiers and linear integrated circuits" . The unfortunate part about this book is that a lot of his circuits are based on dual power supplies.
Can you supply a formula to get the UT and LT of the triangle wave in your schematic? The book quoted gives this on a dual power supply basis. This should then give everything necessary to get a good triangle wave.
I will check out your circuit in LTspice.
 

crutschow

Joined Mar 14, 2008
23,309
Below is the basic circuit I have.
You adjust the value of Vref (pgnd) by changing R4 to compensate for the LM324 output not going fully to the plus supply rail and thus control the symmetry of the wave.

upload_2019-10-16_22-49-55.png
 
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