An Integrated DCDC Converter with Online Monitoring of HotCarrier Degradation An integrated DCDC converter with online monitoring of the degradation induced by hotcarrier stress (HCD) in new generation power LDMOS transistors is proposed. In particular, when a relatively high drain voltage is applied during onstate regime (switching phase), degradation mechanisms lead to an increase of the transistor onresistance (R ON ). To this purpose, the converter is able to dynamically estimate the R ON  of the power LDMOS and to provide its value to the user during normal operation. The presented solution, developed in STMicroelectronics 90nm BCD technology, features a noninvasive current sensing and voltage sampling architecture, which is applied to a common DCDC boost converter to evaluate the resistance of the power LDMOS. Without lack of generality, this specific sensing structure can be applied to any kind of converter, e.g. buck or buckboost, as it does not require any change in the main conversion circuit.

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.