Detection circuit using a differential capacitive sensor with input-common-mode control in a sense interface
    21.
    发明公开
    Detection circuit using a differential capacitive sensor with input-common-mode control in a sense interface 有权
    测量与输入共模范围的控制电路中的传感器接口,用于差动电容式传感器

    公开(公告)号:EP1790988A1

    公开(公告)日:2007-05-30

    申请号:EP05425842.1

    申请日:2005-11-29

    CPC classification number: G01P15/125 G01P15/131

    Abstract: A detection circuit (42) is provided with a differential capacitive sensor (1) and with an interface circuit (30) having a first sense input (7a) and a second sense input (7b), electrically connected to the differential capacitive sensor (1). Provided in the interface circuit are: a sense amplifier (12) connected at input to the first sense input and to the second sense input (7a, 7b) and supplying an output signal (V o ) related to a capacitive unbalancing (ΔC s ) of the differential capacitive sensor (1); and a common-mode control circuit (32), connected to the first sense input (7a) and to the second sense input (7b) and configured to control a common-mode electrical quantity present on the first sense input (7a) and on the second sense input (7b). The common-mode control circuit (32) is of a totally passive type and is provided with a capacitive circuit (34, 35), which is substantially identical to an equivalent electrical circuit of the differential capacitive sensor (1) and is driven with a driving signal V r ‾ in phase opposition with respect to a read signal (V r ) supplied to the differential capacitive sensor.

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