Practical Implementation of a High-Frequency Current-Sense Technique for VRM

摘要

To track the inductor current in high-frequency dc/dc converters is not effortless, particularly when high output currents and low output voltages are demanded by the load. This paper proposes a simple technique to obtain a good accuracy in the inductor current measurement in voltage regulator module (VRM) applications. The main idea is to obtain an equivalent voltage image which can be used for the high-frequency pulsewidth modulation controller to generate the converter control law. This strategy of measurement is generic, and it has been previously validated by simulations. Afterward, some experimental results are obtained by using several prototypes of dc/dc converters delivering a very low output voltage and owning several loads from 10-mA to 100-A currents. This wide range covers the power requirements of portable and embedded VRM applications. Moreover, this sense technique has also been validated in a digital high-frequency current-mode-controlled dc/dc converter.