Evaluation of MOS-FET RDSon resistance for current measurement purposes in power converter's applications

摘要

This paper presents metal oxide semiconductor field effect transistor (MOS-FET) R resistance evaluation in order to perform the MOS-FET current-measurement. For calculation of R the thermal model of the MOS-FET is explored. For accurate R evaluation in the real time the voltage U is measured during the switch-on transistor operation mode. This measurement is synchronized by PWM triggering in order to measure the average voltage value and consequently the average current during the converter sampling time period. This measurement approach is verified by real-time measurement during the operation of the DC-DC step-up converter. The program algorithm is performed on 32-bit ARM M4 MCU, STM32F407.