Characterization of voltage regulators by automated equivalent series resistance

A capacitor with a suitable equivalent series resistance (ESR) characteristic is typically connected to the output terminal of a voltage regulator. This ESR must be characterized during the manufacturing process to identify the range of ESR values and to stabilize voltage regulator operation. This ESR range is characterized manually in current manufacturing practice. However, it is tedious, time-consuming, and limits manufacturing productivity rate. Therefore, the ESR characterization process should be simplified and its effectiveness enhanced. In line with this objective, this work mainly aims to automate the ESR characterization process of voltage regulators. Simulation was performed as the reference for subsequent ESR characterization experiments. After investigating manual characterization outcomes, automated ESR characterization was conducted. A stepper motor controlled by the microcontroller was used to automatically change the ESR values. Results show that the automated ESR characterization approach is simple and can effectively reduce characterization time.