| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a physical quantity detection device comprising a structure capable of reducing an area of an integrated circuit of a filter circuit by reducing an area of a capacitor while increasing a capacity of the capacitor.SOLUTION: A junction capacitance of a transistor 53 formed on a semiconductor substrate 70 is adopted as a capacitor 51 of a filter circuit part 50. In concrete terms, a base region 74 and a collector region 76 of the transistor 53 have the same potential. In addition, a first reference voltage part 20 applies a first reference voltage to an emitter region 75, and a second reference voltage part 30 applies a second reference voltage to the base region 74. Thereby, because a reverse bias is applied to a junction part between the base region 74 and the emitter region 75 in the transistor 53, a junction capacitance is generated. This junction capacitance is amplified by a capacitance amplifier circuit part 54.</p> |
