Implementation of a DCDC Converter with Stepwise Charge and Improved Battery Lifetime An integrated buckboost DCDC converter for interfacing battery sources to capacitive loads such as supercapacitors is presented. The converter features a current regulation circuit on the source side, which applies a predefined constant DC current to the battery source, thus preventing the application of sharp current pulses generally associated with conventional DCDC switching activity and resulting in longterm battery degradation. In fact, flat current shaping positively affects lifetime of battery sources. A specific digital control technique is proposed, which guarantees low energy losses during conversion by implementing a stepwise pseudoadiabatic energy transfer that limits the maximum current inside the circuit and reduces the damping effect on current oscillation due to resistive paths.

Digital Low Power Mode Control Technique for HighFrequency Synchronous DCDC Buck Converters This paper presents a low power mode control technique for digitally controlled synchronous buck converters optimized for the heavy load regulation. The proposed control mode achieves compact area and low complexity thanks to an efficient logic partitioning and reuse of the digital controller. The inductor peak current is controlled with a predictive algorithm that does not require current sensing. A prototype of a digitally controlled synchronous 5xe2x80x940.9 V, 1.5 A buck DCDC converter that embeds the low power control technique is implemented. A custom IC in a 28nm CMOS process has been designed for the digital controller and the gate drivers. Experimental results indicate that the high efficiency range is extended, obtaining an efficiency improvement up to 43% at light load.