A Nonintrusive Digital Current Sensing Method for DC-DC Converters With Wide Load Range

Abstract

Current estimators for dc-dc converters reduce the requirement of current transducers (e.g., sense resistor, Hall sensor) which may be either expensive, invasive, and (or) require additional signal conditioning circuits. High-frequency inductor currents within dc-dc converters can be estimated instantaneously using voltage measurements taken at its terminals. The voltage measurement at the switching terminal of the inductor is assisted by a comparator, whose output state is related to the corresponding voltage magnitude. This letter presents a novel unified current estimation method in which a single comparator is required to detect the switch node status both in continuous and discontinuous modes of operation. The other measurements required for this method include sensing dc voltage magnitudes, which are essential measurements for a regulated dc-dc converter system; hence the proposed methodology can be easily integrated into existing digital control schemes. The proposed approach has been applied to first-order dc-dc converters and has been validated using a laboratory prototype of a digitally controlled boost converter system using an field programmable gate array (FPGA). � 2017 IEEE.