It is known that ripple-based control of a switching dc-dc converter benefits from a faster transient response than a conventional PWM control switching dc-dc converter. However, ripple-based control switching dc-dc converters may suffer from fast-scale oscillation. In order to achieve fast transient response and ensure stable operation of a switching dc-dc converter over a wide load range, based on a conventional pulse train control technique, a peak capacitor current pulse train (PCC-PT) control technique is proposed in this paper. With a buck converter as an example, the operating modes, steady-state performance and transient respond performance of a PCC-PT controlled buck converter are presented and assessed. To eliminate fast-scale oscillation, circuit and control parameter design consideration are given. An accurate discrete iteration model of a PCC-PT controlled buck converter is established, based on which, the effects of circuit parameters on stability of converter operating in a DCM mode, mixed DCM-CCM mode, and CCM mode are studied. Simulation and experimental results are presented to verify the analysis results.
['Jin Sha', 'Duo Xu', 'Yiming Chen', 'Jianping Xu', 'Barry W. Williams']
A Peak-Capacitor-Current Pulse-Train-Controlled Buck Converter With Fast Transient Response and a Wide Load Range