Adaptive on-time control with adjustable virtual ripple and offset cancellation for buck converter

Ripple-based adaptive on-time (RBAOT) control with virtual ripple is a conceptually simple, fast dynamic transient response at lower duty cycle application and lower component count. This control scheme solves the instability issue of subharmonic oscillation when ceramic capacitors are used. These characteristics make the regulators particularly well-suited for power management applications in portable electronic devices and computers. However, this control scheme has some drawbacks of poor dynamic transient response at a specified duty cycle range and inherent output voltage offset problem. This study discussed the aforementioned shortcomings. A new method called RBAOT control with adjustable virtual ripple was proposed to improve dynamic transient response. A new output voltage offset cancellation was also proposed in this study. Simulation and experimental results show that the proposed concept achieved fast dynamic transient response without output voltage offset.