A single mode load tracking voltage mode controller with near minimum deviation transient response

This paper introduces a practical single-mode quasi constant-frequency controller that provides practically minimum output voltage deviation during load transients. This control scheme eliminates the need for two separate controllers for steady-state and transient operation and the associated potential mode transition problems which are characteristic of numerous fast response solutions. The controller only relies on the detection of changes in the output capacitor current polarity and a simple PI compensator to provide fast transient response and tight voltage regulation. The effectiveness of this mixed-signal controller is demonstrated with a 600 kHz, 15 W single-phase buck converter based experimental prototype. During load transients, the inductor current is shown to be corrected within one switching cycle with near-minimum output voltage deviation.