Analysis of the low-frequency oscillation phenomenon in constant-on-time controlled boost converter

In this paper, it found that the low frequency oscillation phenomenon causing large inductor current and output voltage variations exists in the constant-on-time (COT) controlled boost converter, while the time constant of the output capacitor is below a critical value. The critical value is deduced, which is related to the main circuit parameters such as input voltage, inductance and load current. In other words, it indicates that the time constant only depends on main circuit parameters rather than control parameters, which is quite different from the COT controlled buck converter. Simulation and experimental results are given to verify the theoretical analyses.