An Emulated Curve Assisted Fast-Transient Buck Converter With One-Cycle Charge Balance

This article proposes an emulated peak/valley curve-assisted fast-transient buck converter that achieves almost one-cycle charge balance (OCB) load transient response. The previous OCB works require three-parameter calibration to mimic the output capacitor’s RLC, and high-speed inductor current sensor. Comparatively, this work fulfills a one-parameter calibration with reduced design complexity. Additionally, we employ a modified double adaptive bound (DAB) hysteretic control to enhance both transient detection speed and output voltage regulation. The prototype chip fabricated in a 180-nm BCD process, exhibits a measured maximum deviation-from-ideal (DFI) rate of 5.5% for output voltage undershoot/overshoot (US/OS) and recovery time under different load-step conditions. This implies that the transient performance is close to the theoretical optimum with the proposed OCB scheme. The measured load regulation is improved to 0.05%/A by the modified DAB scheme.