Tool/software:
Hello, I'm trying to measure the feedback loop transfer function on our power supply. I'm using the same procedure explained in https://www.ti.com/lit/an/snva364a/snva364a.pdf. I'm measuring voltage on both sides of the injection resistor (50 ohms) with an oscillocope but I don't see any significant gain at low frequency (under 1kHz). Both signals are about the same amplitude but phase shifted. Over 1kHz, it becomes very difficult to measure because of the noise. Every application notes I see on the subject shows a typical bode plot with a 0dB crossover. Our power supply output voltage seems to be stable though. Any idea?
Thanks!
