Derivation of loop gain from output impedances in DC-DC buck converter

We propose a method to derive the loop gain from the open-loop and closed-loop output impedances in dc-dc buck converter. This enables to measure the loop gain without injecting a signal into feedback loop, i.e. without breaking the feedback loop; hence the proposed method can be applied for the control circuits implemented on an IC. Our simulation and experiment results show that the loop gain obtained from the proposed method matches very well with the one from the conventional method.