| 摘要 |
The present invention provides a capacitance detection circuit for inhibiting noise. The capacitance detection circuit (30) detects a change in capacitance between a pair of electrodes of a physical quantity sensor, with these electrodes generating the change in capacitance in response to a change in physical quantity. The capacitance detection circuit (30) has: a carrier signal generating circuit (21) that supplies a carrier signal to one of the electrodes; an operational amplifier (Q31) that has an inverting input terminal to which the other one of the electrodes is input; a dummy capacity (Cd) that is connected in parallel to the pair of electrodes; and a carrier signal conditioning circuit (31) that inverts a phase of a carrier signal supplied from the carrier signal generating circuit to the dummy capacity and adjusts a gain to inhibit the dummy capacity. |
