DC-DC Converter with Improved Dynamic Response and Efficiency Using a Calibrated Auxiliary Phase

A digital adaptive slope control (DASC) technique is presented to improve the dynamic response and efficiency of a current programmed mode (CPM) buck converter employing a low-cost auxiliary phase. Compared to the existing nonlinear control techniques, the advantages of the proposed control scheme include superior voltage droop and settling time, and on-line calibration to compensate for tolerance in the inductance. The proposed technique is experimentally verified on a 500 kHz, 10 V to 2.5 V CPM buck converter prototype. Charge balancing and optimal transient response are achieved for a range of positive and negative load steps. In addition, compared to a representative single phase converter, the proposed system not only has better dynamic response but also achieves 2 % heavy-load and 10 % light-load steady-state efficiency improvement. The impact of the auxiliary phase operation on the converter’s dynamic efficiency is also evaluated at different load step amplitudes and frequencies.MAS