I am trying to understand how the circuit shown below works. It converts a PWM signal to a 1-10V analog signal. The circuit is from this link.
I want to understand how it works because I want to design a circuit that controls a LED driver (such as this one for example) using an analog signal 1-10v. I have several questions:
- The operational amplifier is configured as a voltage follower. In the schematic, its supply voltage is not specified. To guarantee that the operational amplifier can provide a 10 V output, should it have a supply voltage of more than 10V?
- The voltage at R8 is at least 9.6 V (when the optocoupler drives, it is in saturation, Ic=10mA). What is the correct way to dimension the low pass filter so that a duty cycle of 10% corresponds to 1V, 20% to 2V, etc?
- I am also looking at the layout and would not it be necessary to connect the track that I marked in the image?