Time-varying current observer with parameter estimation for multiphase low-voltage high-current voltage regulator modules

Current sharing in interleaved converters is an essential issue for low-voltage, high-current voltage regulator modules (VRMs). The most common method is to sense the average voltage across low-side switches to obtain phase currents. In this paper, an instantaneous current sensing method is presented to observe instant load current and phase currents for multiphase buck converter. Since the load value is time varying, an adaptive control method is applied to estimate load changing. The proposed current observer can also be used for other topologies requiring current sensing. A digital observer is designed and implemented using a DSP controller.