I am working on a fun side project where I am creating a PWM waveform using the LM324 and a small solar panel. I am using the LM324 for the astable multivibrator, integrator, and comparator. The comparator inputs are the integrated signal (triangle wave) and the voltage level of the solar panel. The generated PWM waveform is outputted to a motor driver (L9110H) that is built into a little fan and motor set up (link)
My PWM generator works great before I plug the PWM output into the input of the driver/motor/fan set up. Before I plug it in I can see the duty cycle change from about 70% to 30% depending on how much light is incident on the solar panel. However when I connect the PWM output of my circuit to the input PWM, it starts acting a little weird. It appears most of the time the PWM duty cycle will not change depending on the solar panel, and sometimes the duty cycle will jump to like 99%. I tried using a unity gain buffer, thinking the motor load was affecting my signal somehow, but that's not really helping. What I expect to see is the fan slowing down when I shade the solar panel, and speed up when it is lit. Any advice or instruction would be most appreciated!