An integrated current sense technique for multiphase buck converters to improve accuracy and reduce solution footprint

Accurate and lossless current sensing is a must for high performance multiphase buck converters used in the latest voltage regulation modules (VRMs). This paper presents a sync FET on-state resistance based approach for reconstructing a highly accurate inductor current signal that is immune to changes in operating conditions and temperature. This technique replaces DCR based sensing and can be used with any controller which requires inductor current information. The sense circuitry is built into the MOSFET driver, which in turn is co-packaged with the MOSFETs for reduced total footprint and ease of design. In addition, the accuracy that can be achieved with this technique is significantly better than the typical accuracy achieved with DCR sensing.