A magnetic thin film inductor and its application to a MHz switching dc-dc converter

A Fully Integrated Thin-Film Inductor and Its Application to a DC-DC Converter

“…The Q factors varied from 4.1 to 5.7 in the frequency ranges of 3 to 10 MHz, while the Q factors were less than 3 at frequencies under 2 MHz. These measured data are comparable to those of thinfilm inductors with sandwiched magnetic layers [1]- [2]. Figure 5 shows a microphotograph of the DC-DC converter integrated with the monolithic thin-film inductor.…”

“…Some papers [1]- [5] have reported on practical uses of discrete thin-film inductors for small DC-DC converters, but it has been difficult to integrate the thin-film inductor with the DC-DC converter using a CMOS-compatible process.…”

FeCoBN Magnetic Thin Film Inductor for MHz Switching Micro DC-DC Converters

“…For a simple discussion, the power loss PL of the thin film inductor operating in the dc-dc converter is approximately expressed as follows [1]; (6), where Rdc is the dc coil resistance, Ido is the do compo nent of the coil current, Ip is the peak value of the ac triangular coil current, and (7), …”

“…The authors reported the magnetic thin film inductors for 5 MHz switching boost dc-dc converter [1] [2]. The developed magnetic thin film inductors consisted of an inner planar spiral coil between the top and bottom soft magnetic films.…”

“…Recently, a great interest has been attracted in the planar magnetic devices such as thin film inductor and thin film transformer for low power dc-dc converters [1] [5]. The magnetic thin film devices operating at high frequencies have many advantages over the conventional bulk magnetic devices ; better thermal management and higher power density.…”