A novel current-sharing control technique for low-voltage high-current voltage regulator module applications

Future generations of microprocessors are expected to exhibit much heavier loads and much faster transient slew rates. Today's Voltage Regulator Modul e (VRM) will need a large amount of extra decoupling and output filter capa citors to meet future requirements, which will basically make the existing VRM topologies impractical. As a candidate topology, the interleaved quasis quare-wave (QSW) VRM exhibits very good performance, such as a fast transie nt response and a very high power density. The difficulty with the applicat ion of the interleaved parallel technology is the current-sharing control. In this paper, a novel current-sensing and current-sharing technique is pro posed. With this technique, current sharing can be controlled simply in par allel converters without a current transformer and current-sensing resistor s. In addition, this technique can be easily integrated with an IC chip. Th e four-module paralleled QSW VRM is used to evaluate this technique, Experi mental results verify that with this technique, the VRM has a high power de nsity, high efficiency and a fast transient response, The concept of the cu rrent sharing technique is also generalized and extended.