Why do you have an optocoupler? Why not just PWM through an RC network?
Using optoisolator wanted to separate the microcontroller from the higher voltage.
The Op Amp rail needs to be a rail, or you need to use a 15V supply voltage. An LM358 will only go to 1.5V supply voltage below its.
What could replace the LM358 chip to improve my system?
Or use a digital pot as part of the feedback / voltage network set on a linear regulator.
I tried to use the AD7376 and AD5290, but both can withstand up to 15V and low currents. I plugged it into the inverter instead of potentiometer, worked for a while, and then he burned.
This DAC chip SPI interface is available in surface mount or PDIP for $ 6 each, minimum of 2 from Linear Technologies. It can run on up to 15V and so can output 0-12V Directly.
I’m afraid that this chip LT1257 does not allow me to power the 4 fans that need about 1.6A at 12V.
Will such a system as the scheme allows you to adjust the output voltage?