Application of voltage feedback circuit

Voltage feedback (VFB), used in analog circuits, is a kind of feedback. If the feedback amount is proportional to the output voltage, it is voltage feedback, and there is current feedback (CFB). In an analog circuit, if the feedback amount is proportional to the output voltage (sometimes not necessarily the output voltage, but the voltage at the sampling), it is voltage feedback; if the feedback amount and the output current (sometimes not necessarily the output current, but The current at the sampling point is proportional to the current feedback. In the judgment of voltage feedback and current feedback, the load short circuit method can generally be used. The load short circuit method is actually a reverse reasoning method, assuming that the load resistance RL of the amplifying circuit is short-circuited (at this time), if there is still a feedback amount in the input loop, that is, current feedback; if the input loop is no longer There is feedback, that is, voltage feedback.
Voltage negative feedback stabilizes the output voltage, while current negative feedback stabilizes the output current. Differentiating between voltage feedback and current feedback is only meaningful when the load resistance RL changes. If the RL is fixed, since the output voltage is proportional to the output current, the output current is also stabilized while stabilizing the output voltage, and vice versa, the two effects are the same. However, when the load resistance RL changes, the effect of the two is completely different. When the voltage negative feedback stabilizes the output voltage, the output current will be more unstable. When the current negative feedback stabilizes the output current, the output voltage will be more unstable.