I'm modifying a step-up circuit based on UC3843 SMPS Controller to add a current limiting feedback to it. I'm using a low-side sense resistor (Rsense) amplified by an LM358:
The feedback seems to work but there is a problem with the op amp: its output is slowly rising from the time i turn it on by about 1mV/s making the output current of the step-up module slowly going down. The LM358 behaves like this even when disconnecting its output. I also tried replacing it to no avail.
Can you help me solve solve this issue?