I'm working on a project where I'm trying to steer an analog servo using a PWM-wave generated by this circuit. I found the circuit design from this article. It consists of three operational amplifiers and it's duty cycle is varied by changing the V_in input.
I've run simulations of the circuit in LTSpice, which produce the expected output. Without any servo connected to the output, I see the same waveform on an oscilloscope when I check the output in real-life. In this case, I power the circuitan with a normal power supply. I have a picture of the transient simulation here: where V_out is depicted in the graph.
The issue arises whenever I connect the V_out output to the servo PWM input, I can't get a clear reading on the oscilloscope for V_out anymore. It's distorted and the servo won't stand still either, it moves erratically. When I power the servo with the same frequency and voltage from a function-generator, it works. In both cases the servo's Power and Ground is hooked up to a normal power supply.
Can anyone explain why connecting the servo is causing this distortion? Is there anything I can do to fix this issue and get a clear reading on the oscilloscope when the servo is connected? This all runs on working power supplies so it's not an issue of sufficient power.
TLDR: Trying to steer an analog servo with a generated PWM-wave. I've generated the PWM-wave with this circuit. It works in a LTSpice simulation as can be seen in this graph where V_out is plotted. The circuit also works in real-life when NOT connected to the servo's PWM input. The servo itself also works when supplied by a function generator by a PWM-wave with the same properties as the generated one. The issue is that when I connect the generated PWM-wave with the servo input: V_out gets distorted and the servo moves erratically.
