A I_Max $\vert_{\max^{,}}$ Fully Integrated Multi-Phase Voltage Regulator with 91.5% Peak Efficiency at 1.8 to 1V, Operating at 50MHz and Featuring a Digitally Assisted Controller with Automatic Phase Shedding and Soft Switching in 4nm Class FinFET CMOS

Design and Integration of Beyond-10MHz High Switching Frequency DC-DC Converter

“…On the other hand, as will be discussed in Sect. 3, some recent works with integrated magnetic core inductor are improving FoM [15], [16], [35], [39], [40], [43], [45], [50]. In Fig.…”

“…The first one utilizes sub-5V process, such as CMOS legacy process ranging from 0.35μm to 130nm CMOS process for portable applications with f sw up to 50MHz while some early works adopt very high f sw above 100MHz [1]- [17]. The second type is targeted for high performance CPU power delivery whose f sw is mainly above 50MHz using advanced CMOS process including FinFET [18]- [50]. These two types often integrates inductor on-chip or in-package for footprint reduction, higher power density, and better load transient response.…”

“…Higher timing resolution also allows reduced dead-time and switching transition time of the switching node, which can reduce P DT and P ST , respectively. On the other hand, the voltage ratings of the thin oxide FET in the advanced technology node is typically around 1V, thus, V IN beyond this voltage requires FETstack power stage [13], [14], [25], [30], [31], [34], [35], [37], [38], [41]- [46], [48]- [50], [67] as shown in Fig. 5.…”

“…There are two types of candidates for the core material. One is the thin magnetic film like permalloy (Fe 45 Fe 55 ) and CZT (CoTaZr) [27], [33], [35], [37], [39], [40], the other is epoxy/magnetic-filler composite [16], [43], [45], [50], [84], [85]. Some thin film processes are compatible with CMOS, so the magnetic core inductor can be integrated onchip.…”

“…For the integrated inductors, new magnetic filler materials that have smaller core loss to improve efficiency or higher permeability to increase inductance density are rapidly developing. For instance, carbonyl iron (CIP)/epoxy composite sheet shows very low eddy current loss even at 100MHz thanks to the very small grain diameter of 1.1μm [43], [45], [50], [84]. This is suitable for high-end CPU IVR and has been adopted to magnetic inductor array (MIA) [43] or coaxial metal inductor loop (Coax MIL) [45], [50] for 10 th generation Intel Core microprocessors and beyond.…”