The study of the low-power, digital output signal processing circuits for capacitive sensors

• Project/Area Number: 25420329
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: University of Yamanashi
• Principal Investigator: OGAWA Satomi 山梨大学, 総合研究部, 准教授 (40252168)
• Research Collaborator: SATO Takahide ; YOKOTE Hiroji
• Project Period (FY): 2013-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2014: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2013: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: 容量型センサ / 容量・時間変換器 / 時間・ディジタル変換器 / スイッチドキャパシタ回路 / センサ信号処理回路 / CMOSアナログ回路 / センサ信号処理 / CMOS集積回路 / 差動容量型センサ

Outline of Final Research Achievements

A high-accuracy CMOS interface for differential capacitive sensors using a time-to-digital converter (TDC) is presented. The proposed TDC achieves high resolution using two clock signals of which the periods are different. The performances of the proposed CMOS interface are simulated by HSPICE using 0.18 um CMOS process parameters. The resolutions of 11.3 bits are achieved with calibration. The maximum nonlinear errors are smaller than plus/minus 0.55 LSB. The measured results of a prototype circuit indicate that the resolutions of 10.3 bits is achievable.
To realize higher-accuracy capacitance-to-time conversion, three differential-capacitance-to-time converters (DCTC) for capacitive sensors were proposed. Simulated results have demonstrated that 12-bit resolution is achievable. The power consumption of the proposed circuits is 25.6 microwatts for 1.8 V
The proposed circuit is suited for co-integration with MEMS-type sensors and microcontroller-based measurement system.

Research Products

• [Journal Article] A Low-Power, High-Accuracy Capacitance-to-Time Converter for Differential Capacitive Sensors (2017)
  • Author(s): Satomi Ogawa
  • Journal Title: Proceedings of the IEEE 8th Latin American Symposium on Circuits and Systems Volume: - Pages: 13-16
  • Peer Reviewed
• [Journal Article] A High-Accuracy Differential-Capacitance-to-Time Converter for Capacitive Sensors (2015)
  • Author(s): M. Nagai and S. Ogawa
  • Journal Title: Proceedings of the IEEE 58th International Midwest Symposium on Circuits and Systems Volume: - Pages: 1-4
  • DOI: 10.1109/mwscas.2015.7282200
  • Peer Reviewed
• [Journal Article] A CMOS Interface for Differential Capacitive Sensors Using a Time-to-Digital Converter (2014)
  • Author(s): 1.S. Ogawa
  • Journal Title: Proceedings of the IEEE 57th International Midwest Symposium on Circuits and Systems Volume: _ Pages: 945-948
  • DOI: 10.1109/mwscas.2014.6908572
  • Peer Reviewed
• [Presentation] 差動容量型センサの信号処理回路の精度改善 (2017)
  • Author(s): シュレスタ ソミ, 小川 覚美, 佐藤 隆英
  • Organizer: 電気学会全国大会
  • Place of Presentation: 富山大学（富山県・富山市）
  • Year and Date: 2017-03-15
• [Presentation] 荷重測定用の容量型センサの試作及び評価と信号処理回路の開発 (2017)
  • Author(s): 棚田 康介, 小川 覚美, 佐藤 隆英
  • Organizer: 電気学会全国大会
  • Place of Presentation: 富山大学（富山県・富山市）
  • Year and Date: 2017-03-15
• [Presentation] C/T変換を用いた高精度容量型センサ・インターフェイス (2016)
  • Author(s): 小川 覚美
  • Organizer: 電気学会全国大会
  • Place of Presentation: 東北大学（宮城県仙台市）
  • Year and Date: 2016-03-16
• [Presentation] C/T変換を用いた容量型センサCMOSインターフェイスの高精度化に関する検討 (2015)
  • Author(s): １．永井 正成, 小川 覚美
  • Organizer: 電気学会全国大会
  • Place of Presentation: 東京都市大学(東京都世田谷区)
  • Year and Date: 2015-03-24 – 2015-03-26
• [Presentation] C/T変換を用いた容量型センサCMOSインターフェイスの高精度化 (2014)
  • Author(s): ２．永井 正成, 小川 覚美
  • Organizer: 電気学会東京支部沼津・山梨支所研究会
  • Place of Presentation: 東芝キャリア(株)(静岡県富士市)
  • Year and Date: 2014-11-21
• [Presentation] C/T変換を用いた容量型センサCMOSインターフェイス (2014)
  • Author(s): ３．小川 覚美, 永井 正成
  • Organizer: 電気学会電子･情報･システム部門大会
  • Place of Presentation: 島根大学(島根県松江市)
  • Year and Date: 2014-09-03 – 2014-09-06
• [Presentation] 時間・ディジタル変換器とそのセンサ信号処理への応用 (2013)
  • Author(s): 石原 拓馬, 橋場 智之, 小川 覚美
  • Organizer: 電気関係学会東海支部
  • Place of Presentation: 静岡大学（静岡県浜松市）
• [Remarks] 山梨大学HP内研究者総覧
  • URL: http://nerdb-re.yamanashi.ac.jp/Profiles/339/0033858/profile.html
• [Remarks] 山梨大学 技術・研究情報
  • URL: http://sangaku.yamanashi.ac.jp/SearchResearcher/contents/63EA013F9592FC44.html
• [Remarks] やまなし技術の宝石箱 山梨大学シーズ
  • URL: http://www.pref.yamanashi.jp/chiikisng/techno-jewel-box/seeds/documents/ogawa2510.pdf