ELECTROSTATIC CAPACITANCE MEASUREMENT DEVICE

• Main Authors: KOIKE SHINICHI, MINAMI HIDEAKI
• Format: Patent
• Language: English; Japanese
• Published: 09.11.2015
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To simplify the configuration of a voltage measurement system and speed up a measurement time in measuring the electrostatic capacitance of a capacitor from a constant-current value I applied to the capacitor, a charge time T, and a differential voltage between an initial voltage and a final voltage at termination of charging.SOLUTION: An electrostatic capacitance measurement device includes a charge detection comparator 15 for comparing the voltage V of a capacitor Cx with a preset charging termination voltage Vd and outputting a charge termination signal when V=Vd, and a timer 11c for counting a charge time. Charge is begun with a constant current I after the capacitor Cx is discharged, and the charge is completed at a time when a charge termination signal is outputted from the charge detection comparator 15. A charge time T during this period is acquired by the timer 11c, and the electrostatic capacitance of the capacitor Cx is calculated by I×T/Vd. The above procedure being basic, determination is made in the middle of charge as to whether the charge current is appropriate or not, a measurement range is changed as necessary on the basis of the determination result, and capacitance measurement is performed again. 【課題】キャパシタに印加する定電流値Ｉ，充電時間Ｔおよび初期電圧と充電終了時の最終電圧の差電圧とから、キャパシタの静電容量を測定するにあたって、電圧測定系の構成を簡素化するとともに、測定時間の高速化をはかる。【解決手段】キャパシタＣｘの電圧Ｖと、予め設定されている充電終結電圧Ｖｄとを比較してＶ＝Ｖｄのとき充電終結信号を出力する充電検出用比較器１５と、充電時間を計時するタイマ１１ｃとを備え、キャパシタＣｘを放電させた後、定電流Ｉで充電を開始し、充電検出用比較器１５より充電終結信号が出力された時点で充電を完了し、この間の充電時間Ｔをタイマ１１ｃにより取得して、キャパシタＣｘの静電容量ＣをＩ?Ｔ／Ｖｄにより算出することを基本とし、充電途中で充電電流が適正かどうかの判定を行い、その判定結果に基づいて、適宜測定レンジの変更を行って、再度容量測定を行う。【選択図】図１