An accurate lossless current sensing approach for a DC-DC converter with online calibration

Abstract

Lossless inductor current sensing is preferred in the current controlled DC-DC converters to improve the power efficiency. However the sensing accuracy for the conventional lossless method is not as good as the direct current measurement with shunt resistors. In this paper, a novel online calibration method using the matched complementary filter (MCF) current sensing is proposed to overcome the poor accuracy problem in particular due to the parameter variation. The result shows that the proposed method can achieve 1% accuracy on parameter estimation and 5% accuracy on current sensing.