Current Sensing Method by RC Network (1998)
One of the difficulties of implementing the multiphase buck converter that powers the microprocessor is the issue of current sharing among parallel modules. One of the common techniques for insuring current sharing is to implement some form of current-sensing technique, usually by sensing the inductor current or switch current. However, the conventional implementation of current sensing does not lend itself to easy implementation in a control IC. CPES has developed a patented technology, "A Novel Fast-Transient Response and Minimal-Sized Regulator Modules with Novel Current Sensing and Current Sharing Technology" (U.S. Patent 6,414,469). This proposed approach employs a simple R-C network to emulate the current going through the energy storage inductor, and is very easy to implement in a control IC for the purpose of current sharing and Adaptive-Voltage-Drop (AVP) control of output voltage. This method was quickly adopted by industry and is referred to in industry as the "DCR" sensing method and has been widely used in many of the IC controllers for this application.