ELECTROSTATIC CAPACITANCE DETECTION CIRCUIT

Title:

ELECTROSTATIC CAPACITANCE DETECTION CIRCUIT

Document Type and Number:

WIPO Patent Application WO/2013/073161

Kind Code:

A1

Abstract:

Provided is an electrostatic capacitance detection circuit in which noise is suppressed. An electrostatic capacitance detection circuit (30) detects the electrostatic capacitance change between a pair of electrode portions, which generate the electrostatic capacitance change corresponding to a physical quantity change, said electrode portions being provided in a physical quantity sensor. The electrostatic capacitance detection circuit (30) is provided with: a carrier signal generating circuit (21) that supplies carrier signals to one of the pair of electrode portions; an operation amplifier (Q31) that has an inverting input terminal to which the other electrode portion is connected; a dummy capacitor (Cd) that is connected in parallel to the pair of electrode portions; and a carrier signal adjusting circuit (31), which inverts the phase with respect to the carrier signals transmitted from the carrier signal generating circuit to the dummy capacitor, and adjusts the gain to suppress the capacitance of the dummy capacitor.

Inventors:

KISHIRO MASAMI (JP)

Application Number:

PCT/JP2012/007256

Publication Date:

May 23, 2013

Filing Date:

November 12, 2012

Export Citation:

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Assignee:

FUJI ELECTRIC CO LTD (JP)

International Classes:

G01P15/125; G01B7/00; G01L1/14; G01L9/00

Foreign References:

JPH0862266A	1996-03-08
JP2003156524A	2003-05-30
JP2007078648A	2007-03-29
JPH05231973A	1993-09-07
JP2011107086A	2011-06-02
JP2011107086A	2011-06-02

Other References: