| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a capacitance type physical quantity detector capable of suppressing secular change of a circuit. <P>SOLUTION: Input/output of a first differential amplifier 22 is short-circuited by a switch 26, a constant electric potential VN is outputted from the first differential amplifier 22 (i.e., a C-V conversion circuit 20), and an output of amplifying the constant electric potential VN by an amplifier 40 is held in a C sample hold circuit 51c. A hold value of the C sample hold circuit 51c is a value VN+Vg of adding the constant electric potential VN to a gain of the amplifier 40. An output (i.e., a signal output) when the first differential amplifier 22 is not short-circuited by the switch 26 is held in an A sample hold circuit 51a, and a difference between the A sample hold circuit 51a and the C sample hold circuit 51c is outputted by a second differential amplifier 54. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
