TY - GEN
T1 - DC-biased high-power impedance measurement of planar magnetic cores up to 70 MHz
AU - Yamaguchi, M.
AU - Erdenebat, U.
AU - Suzuki, K.
AU - Itagaki, A.
AU - Ishizuka, Y.
N1 - Funding Information:
Introduction- It is necessary to develop a measurement technology of planar magnetic cores at higher frequencies and higher power ranges to develop better power supply on chip (PwrSoc). Besides the miniature magnet-wire wound cores , , DC-biased impedance measurements for planar tiny core is still in challenge to achive reliable/repeatable electric contact for tiny electrodes, and to reduce/calibrate associated stray impedance for better accuracy -. In this work, a DC-biased impedance measurement system usable up to 70 MHz, AC 10 A, DC-bias 5 A is studied through the development of an impedance-matched measurement board that eliminated magnet-wire connection. Design of DC-biased high-power impedance measurement- As shown in Fig.1, DC signal from DC generator will be superimposed at the device-under-test (DUT) with amplified AC signal from impedance analyzer (4294A, Agilent Tech.) through power amplifier (typically NF 4020, NF Corp.) and therefore the DC-bias characteristics of DUT can be measured through the impedance analyzer. The voltage and current dividing circuit are attached to the impedance analyzer for high power inductor measurement; division ratios are 51:1 for voltage and 101:1 for current, respectively. The voltage devider forms a capacitance bridge circuit to keep the voltage ratio as 51:1 at wider frequency range, regardless of the stray capacitance Ci located at the input terminal of impedance analyze as shown in FIg. 1. Impedance matching design- Impedance matching to 50 Ω is provided for on-printed circuit board (PCB) wires to decrease stray impedance and accordingly to improve the measurement accuracy. Dimension of on-PCB wires is also so designed to carry the rated AC and DC currents. CAD software (Proteus 8 Professional) is used to design coplanar waveguide on the popular FR-4 PCB. All wirings are made of patterned cupper sheets providedo on double-sides of the PCB. Completed wiring layout is shown in the left side in Fig. 1. There were no magnet-wirings. Results and Discussion- The completed measurement board was connected to the fixture (16047E, Agilent). Test inductors are; leaded radial inductors, wire-wound inductors and wire wound molded chip inductors ranging from 10 nH to 10 μH in market (TDK TSL0709, SLF10145 and LFC32, respectively). All the measured data were agreed well with the data sheet in the published frequency and DC -bias current ranges. Representative data are shown in Fig. 2. A 4.7-μH leaded inductor resonated at 40 MHz and the inductance is flat up to DC 4 A. A 33-nH chip inductor will not resonate up to 100 MHz while small peak is seen at 70 MHz, indicating that >100 MHz measurement would be possible by reducing the further tiny stray impedance of the PCB. Conclusion- A DC-biased impedance measurement system for planar magnetic core has been developed usable up to 50 MHz, AC 10 A, DC-bias 5 A. Measured data of typical inductors demonstrated the validity of the proposed methodology, and potential >100 MHz measurements. Acknowledgment- The authors are grateful to Eden Attobra, Valeo formarly Tohoku University, Masaki Sato and Kazuma Shiya, Nagasaki University, Yasutoshi Hirano and Sshinya Manabe, Ricoh Electronic Devices Inc. Co. for their valuable help and comments. Supported in part by μSiC, Tohoku University.
© 2017 IEEE.
PY - 2017/8/10
Y1 - 2017/8/10
N2 - It is necessary to develop a measurement technology of planar magnetic cores at higher frequencies and higher power ranges to develop better power supply on chip (PwrSoc).
AB - It is necessary to develop a measurement technology of planar magnetic cores at higher frequencies and higher power ranges to develop better power supply on chip (PwrSoc).
UR - http://www.scopus.com/inward/record.url?scp=85034642065&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85034642065&partnerID=8YFLogxK
U2 - 10.1109/INTMAG.2017.8007783
DO - 10.1109/INTMAG.2017.8007783
M3 - Conference contribution
AN - SCOPUS:85034642065
T3 - 2017 IEEE International Magnetics Conference, INTERMAG 2017
BT - 2017 IEEE International Magnetics Conference, INTERMAG 2017
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2017 IEEE International Magnetics Conference, INTERMAG 2017
Y2 - 24 April 2017 through 28 April 2017