To improve detection accuracy while suppressing the use of resources.SOLUTION: A control circuit 70 includes a counter unit 81 for counting the number of times a transfer switch is turned on and off and thereby specifying a detection count value N at which the result of comparison of the potential of a detection point set at one end of a reference capacitor with a reference potential is reversed. The control circuit 70 also includes a threshold computation unit 85 (83, 82) for computing a threshold Y for determining a change of capacitance occurring to a capacitor being measured, using a linear expression Y=AX+B, where a base count value X for monitoring the detection count value N is made a variable. The threshold computation unit 85 holds an exponent α for the case when the inclination A of the linear expression is expressed by a power of 2 (2^α) and performs bit shift computation based on the exponent α and thereby computes the value of an inclination term AX that corresponds to the base count value X.SELECTED DRAWING: Figure 7

    【課題】リソースの使用を抑えつつ、検出精度の向上を図る。【解決手段】制御回路70は、転送スイッチのオン/オフ回数をカウントすることにより、その基準コンデンサにおける一方の端子に設定された検出点の電位と参照電位との比較結果が反転する検出カウント値Nを特定するカウンタ部81を備える。また、制御回路70は、その検出カウント値Nを監視するためのベースカウント値Xを変数とした一次式、「Y=AX+B」を用いて被測定コンデンサに生じた静電容量の変化を判定するための閾値Yを演算する閾値演算部85(83,82)を備える。そして、閾値演算部85は、その一次式の傾きAを「2のべき乗(2^α)」で表した場合の指数αを保持するとともに、この指数αに基づいたビットシフト演算を行うことにより、そのベースカウント値Xに応じた傾き項「AX」の値を演算する。【選択図】図7


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    Title :

    CAPACITANCE SENSOR AND OPERATION INPUT DETECTOR FOR VEHICLES


    Additional title:

    静電容量センサ及び車両用操作入力検出装置


    Contributors:

    Publication date :

    2020-02-06


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    Japanese


    Classification :

    IPC:    G01R Messen elektrischer Größen , MEASURING ELECTRIC VARIABLES / B60R Fahrzeuge, Fahrzeugausstattung oder Fahrzeugteile, soweit nicht anderweitig vorgesehen , VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR



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