| 摘要 |
PURPOSE:To obtain a pressure sensor circuit enable to reduce an error as a pressure sensor by connecting a circuit for detecting an offset voltage. CONSTITUTION:When no bias is applied to a control terminal 14, the impedance of a MOS switch 13 is infinite and equivalent to disconnection. When a bias is applied to the terminal 14, the MOS switch 13 has extremely low impedance against sensor bridge resistors 7-10. Namely, the sensor bridges are equivalently balanced from an amplifier 11. Thereby electric power for the output 12 of the amplifer 11 is only the offset voltage of the amplifier 11. At the measurement of normal pressure, an error due to only the amplifier 11, i.e. the offset voltage, can be measured by the terminal 14. Thus, the output of the amplifier 11 which is removed at its error and corresponds to the pressure can be obtained by detecting the measured voltage and the offset voltage and finding out their difference by an external device. |
