This article deals with the calibration method of analog integrated circuits (ICs) designed in CMOS nanotechnology. A brief analysis of various methods and techniques (e.g., fuse trimming, chopper stabilization, auto-zero technique, etc.) for calibration of a specific IC’s parameter is given, leading to motivation for this research that is focused on the digital calibration. Then, the principle and overall design of the calibration subcircuit, which was generally used to calibrate the input offset voltage $V_{IN\_OFF}$ of the operational amplifier (OPAMP). The essence of this work is verification of the proposed digital calibration algorithm for minimization the $V_{IN\_OFF}$ of a bulk-driven fully differential difference amplifier (FDDA) with the power supply voltage $V_{DD}$ = 0.4 V. Evaluation of ASIC prototyped chip samples with silicon-proved results has been done. This evaluation contains comparison of selected parameters and characteristics obtained from both simulations and measurements of non-calibrated and calibrated FDDA configurations.

This article presents the analysis of selected maximum power point tracking (MPPT) algorithms and their influence on developed energy harvester (EH) systems under uniform conditions. The energy harvester is an electronic system that converts available ambient energy to electrical energy and regulates its distribution to the output. The aim is to design an energy harvester with the highest integration rate possible with consideration of area requirements and low power consumption. To improve the overall energy conversion of the developed harvester, we implemented several MPPT algorithms (Pilot Cell, Constant Voltage, Perturb and Observe) into a dedicated MPPT controller that controls the DC-DC converter. Consequently, we experimentally analyzed their impact on the harvester system. Findings show that even simple algorithms with smaller chip areas and lower power consumption can achieve results comparable to more complex ones. The proposed, manufactured and experimentally evaluated EH chip prototype has proven its expected functionality and is therefore fully capable of supplying energy for low-power electronics and battery-operated devices.