Reduction of the switching frequency and the number of phases in multiphase VRM by applying linear-non-linear control

Voltage Regulator Modules (VRM) are DC-DC converters that regulate the microprocessors power supply voltage. These devices require a very low and well-regulated voltage with high currents and very fast dynamic response. In addition, high efficiency values are needed because of size restrictions. Multiphase interleaving synchronous buck converters are one of the most interesting options to meet these dynamic voltage specifications. In this paper, a cost-effective and high density solution based on a classical multiphase VRM is proposed by using linear-non-linear control. This control technique provides a reduction of the number of phases and the switching frequency compared to classical control strategies based on linear control. This analysis has been validated with experimental results in a VRM prototype with eight interleaved synchronous buck converters.