# US 2019/0170807 A1 · Evaluation method, estimation method, evaluation apparatus, and combined evaluation apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170807 A1 - Document ID: US20190170807A1 - Status: Published application - Kind: A1 - Application number: 16/260,130 - Filed: 2019-01-29 - Published: 2019-06-06 - Earliest claimed: 2017-02-24 - Assignees: Fuji Electric Co., Ltd. - Applicants: Fuji Electric Co., Ltd. - Inventors: Hiroki KATSUMATA; Michio TAMATE; Miwako FUJITA; Tamiko ASANO; Yuhei SUZUKI; Takashi KAIMI; Yuta SUNASAKA; Tadanori YAMADA; Ryu ARAKI; Bao Cong HIU - Web page: https://patentgrep.com/patent/US20190170807A1 ## CPC - G01R 29/26: Measuring noise figure; Measuring signal-to-noise ratio - G01R 31/2626: {for measuring noise (measuring noise factor in general G01R29/26)} - G01R 29/08: Measuring electromagnetic field characteristics - G01R 31/002: {where the device under test is an electronic circuit} - G01R 31/26: Testing of individual semiconductor devices (testing of photovoltaic devices H02S50/10; testing or measuring during manufacture or treatment {H10P74/00}) - G01R 31/2621: {for testing field effect transistors, i.e. FET's} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method and an evaluation apparatus are provided, including: causing a semiconductor device to perform a switching operation; measuring voltage variation occurring between main terminals of the semiconductor device during the switching operation; and outputting an evaluation benchmark for radiated noise of the semiconductor device based on the voltage variation. The outputting the evaluation benchmark may include calculating the voltage variation in the semiconductor device for each frequency component as the evaluation benchmark. ## Claims ### Claim 1 An evaluation method comprising: causing a semiconductor device to perform a switching operation; measuring voltage variation occurring in the semiconductor device during the switching operation; and outputting an evaluation benchmark for radiated noise of the semiconductor device based on the voltage variation. ### Claim 2 (depends on 1) The evaluation method according to claim 1, wherein the outputting the evaluation benchmark comprises calculating the voltage variation in the semiconductor device for each frequency component as the evaluation benchmark. ### Claim 3 (depends on 1) The evaluation method according to claim 1, wherein the switching operation comprises at least two of a turn-on operation, a turn-off operation, a reverse recovery operation, and a forward recovery operation of the semiconductor device. ### Claim 4 (depends on 1) The evaluation method according to claim 1, wherein: the semiconductor device comprises a first device and a second device connected in series; and the measuring comprises measuring variation in a voltage between the first device and the second device. ### Claim 5 (depends on 1) The evaluation method according to claim 1, wherein: the semiconductor device comprises a first device and a second device connected in series; and the measuring comprises measuring variation in a voltage across the first device and the second device. ### Claim 6 (depends on 4) The evaluation method according to claim 4, wherein the measuring comprises measuring variation in a voltage of the semiconductor device relative to a reference potential, the reference potential being a potential of a conductive member to which the semiconductor device is attached via an insulating material. ### Claim 7 (depends on 1) The evaluation method according to claim 1, further comprising: comparing the evaluation benchmark output for the semiconductor device and an evaluation benchmark output for a reference device different from the semiconductor device; and evaluating an intensity of the radiated noise of the semiconductor device relative to the reference device based on a result of the comparison. ### Claim 8 (depends on 1) An estimation method for estimating radiated noise of an apparatus provided with the semiconductor device, the estimation method comprising: acquiring a plurality of evaluation benchmarks for the semiconductor device that are output in correspondence with the switching operation under a plurality of conditions by using the evaluation method according to claim 1; and combining the plurality of evaluation benchmarks to estimate the radiated noise of the apparatus. ### Claim 9 (depends on 8) The estimation method according to claim 8, wherein the combination of the evaluation benchmarks is a maximum value or a sum of the plurality of evaluation benchmarks for the semiconductor device. ### Claim 10 (depends on 8) The estimation method according to claim 8, wherein the combination of the evaluation benchmarks is an average value of the plurality of evaluation benchmarks for the semiconductor device. ### Claim 11 (depends on 8) The estimation method according to claim 8, wherein the combination of the evaluation benchmarks is an average value calculated after multiplying the plurality of evaluation benchmarks for the semiconductor device by respective weights corresponding to the plurality of conditions. ### Claim 12 An evaluation apparatus comprising: a signal supplying unit configured to supply a predetermined switching signal to a to-be-evaluated semiconductor device; a detection unit configured to detect voltage variation in the semiconductor device; and an evaluation benchmark output unit configured to output an evaluation benchmark for radiated noise of the semiconductor device based on a result of the detection by the detection unit. ### Claim 13 (depends on 12) The evaluation apparatus according to claim 12, wherein the evaluation benchmark output unit is configured to calculate an electric field strength corresponding to the radiated noise of the semiconductor device based on a frequency component of the voltage variation. ### Claim 14 (depends on 12) The evaluation apparatus according to claim 12, wherein the signal supplying unit is configured to supply a switching signal to perform at least two of a turn-on operation, a turn-off operation, a reverse recovery operation, and a forward recovery operation of the semiconductor device. ### Claim 15 (depends on 12) The evaluation apparatus according to claim 12, wherein: the semiconductor device comprises a first device and a second device connected in series; and the detection unit is configured to measure variation in a voltage between the first device and the second device. ### Claim 16 (depends on 12) The evaluation apparatus according to claim 12, wherein: the semiconductor device comprises a first device and a second device connected in series; and the detection unit is configured to measure variation in a voltage between main terminals of the first device and the second device. ### Claim 17 (depends on 12) The evaluation apparatus according to claim 12, further comprising: a storage unit configured to store the evaluation benchmark output by the evaluation benchmark output unit; and a comparison unit configured to compare the evaluation benchmark output by the evaluation benchmark output unit and an evaluation benchmark for a reference device different from the semiconductor device stored in the storage unit; and an evaluation unit configured to evaluate a relative change in intensity of the evaluation benchmark for the radiated noise of the semiconductor device based on a result of the comparison. ### Claim 18 (depends on 12) The evaluation apparatus according to claim 12, wherein the detection unit is configured to measure variation in a voltage of the semiconductor device relative to a reference potential, the reference potential being a potential of a conductive member to which the semiconductor device is attached via an insulating material. ### Claim 19 (depends on 12) A combined evaluation apparatus, comprising: an acquisition unit configured to acquire a plurality of evaluation benchmarks for the semiconductor device that are output by the evaluation apparatus according to claim 12 in correspondence with the switching signal under a plurality of conditions; a combined evaluation unit configured to combine the plurality of evaluation benchmarks to estimate radiated noise of an apparatus provided with the semiconductor device.