Analysis and interpretation of loop gains of multiloop-controlled switching regulators (power supply circuits)

Two different loop gains of power supplies with current-mode control are considered. Relationships between the different loop gains of the multiloop system and the closed-loop measures of output impedance and audio susceptibility are derived. It is shown that different loop gains can be used to obtain information about relative stability and to enhance a poor design. Different implementations of current-mode control are discussed, and the most common problem encountered in practical circuit applications is shown. This problem is connected with the fact that, for high-power applications, the DC portion of the waveform is much larger than the ramp.<>