Solving Op Amp Confusion with PWM Circuit

[jafferrox]

Hi

In the waveform picture i attached, I don't know why the square wave is floating instead of being on the 0 of the x axis. I also attached schematic of the pwm circuit.

By the way, this is a pulse width modulator circuit made of 4 op amps, U2D is a schmitt trigger to generate sqaure wave, U2C is integrator that integrates square and generate triangle wave, U2A is comparator which is used to generate PWM signal and U2B is used to isolate pwm signal from the load that's going to connect to the output.

Thanks in advance

 

[skeptic2]

The design of the opamp prevents the output from going all the way to the negative supply or all the way to the positive supply. There are other opamps, often called "rail-to-rail, with which the outputs do go to the positive and negative supplies.

 

[NascentOxygen]

You could add a simple 1 or 2 FET buffer stage to cause that signal to hit ground, if that were important.

 

[jafferrox]

thanks for the help guys.

 

[alphy]

Hello,

Thank you for sharing your waveform picture and schematic of the PWM circuit. It seems like you have a good understanding of the components and their functions in the circuit. To address your question about the square wave floating instead of being on the 0 of the x axis, it could be due to a few factors such as incorrect component values, circuit layout, or external interference. I would recommend checking and double-checking all the component values and connections to ensure they are correct and properly integrated into the circuit. Additionally, it may be helpful to simulate the circuit or test it on a breadboard to troubleshoot any potential issues.

It's great to see you using op amps in this circuit. Op amps are widely used in various applications due to their versatility and precision. In this case, the op amps are being used to generate and manipulate different types of waveforms, which is a common application of op amps in signal processing.

Overall, it's important to carefully analyze and test the circuit to ensure it is functioning as intended. I wish you success in solving any confusion and achieving your desired results with the PWM circuit. Keep up the good work!