Twisted core coupled inductor for the microprocessor VR (2004)
The coupled inductor VR of microprocessor has several benefits compared with today's non-coupled inductor VR, such as higher efficiency, faster transient response, lower footprint and cost. However, today's coupled inductor implementation has a longer winding path, which is not preferable for the low voltage and high current application.
To solve this issue, the twisted core coupled inductor is proposed. The concept is quite simple. Today's coupled inductor uses straight core with winding wrapped around. So, it has a long winding length. Against conventional wisdom, it was proposed to keep the winding straight and wrap the core around it. By doing so, we can get the minimized the winding length and less total loss of the inductor.
The twisted core coupled inductor concept and its implementation is shown in the following figure.