Hi Ladies and Gentlemen,
It is related to an existing post here from early 2019. Voltage to PWM Circuit, need to understand frequency
I am trying to make a simple 0-10V to PWM converter (idealy linear on it's full span).
It is pretty simple and I have in hand a reference module that was described in the previous mentioned post. I am trying to reproduce it's behavior and the ramp it generates.
In theory I understand that the Ramp signal generated by a 555 will sit between 1/3VCC and 2/3VCC due to the internal resistor network. And that's what I get from my BredBoard experiment.
Now How can I get the ramp to be between 0V and 2/3VCC? I know the question can be odd, but that is exactly what I get by monitoring the Ramp signal in the little board shown here. Yes the 0V is on the middle of the vertical axis. There is no extra parts like a (-1/3VCC supply to make a vertical translation on the signal). There is only what is shown on this module...
I know I am trying to retro-engineer a Chinese product :-/ But is there anybody that could have an insight that would help bring light on this?
Thanks in advance for your input.