A Current-Sensing Circuit for DC–DC Converters With Bootstrap Characteristics

Current sensing in dc-dc converters is critical for protection and operation purposes of the system. This paper proposes a novel lossless current-sensing technique based on the matching complementary filter topology whose main idea is to transform the current signal to voltage signal. This new technique introduces a thermal compensation block to improve its accuracy, an error elimination block to solve the problem of its floating output voltage, and a bootstrap block to allow this technique to be applied in high-voltage systems. Finally, some experimental results of this novel technique for dc-dc converters are presented, and applications on synchronous rectification are analyzed.