A low-complexity high-performance digital control architecture for voltage regulator modules

This paper presents a new digital control architecture for voltage regulator modules, which employs only two digital-to-analog converters with low resolution (7 bit). The control strategy combines current programming and variable frequency operation, leading to negligible quantization effects. Both output voltage accuracy and stability are improved with respect to traditional digital solutions. The new architecture is designed to provide active current sharing and adaptive voltage positioning functions. A detailed description of the controller is given with reference to a single-phase buck converter. Extension to multiphase converters is straightforward. The control algorithm has been implemented into a commercial FPGA device by using only 2200 equivalent gates. Experimental results from a four-phase converter based on the proposed control architecture are presented.