Abstract: A sensor device includes a pressure-temperature detection unit and a signal processing circuit. The sensor device is configured to detect abnormalities by changing a supply voltage supplied to the pressure-temperature detection unit and to the signal processing circuit, and by monitoring changes in a pressure signal and in a temperature signal caused by changing the supply voltage.

Abstract: A sensor device changes a supply voltage, and examines whether output signals of a signal processing circuit including a pressure signal and a temperature signal change in a manner that follows the supply voltage change caused by a voltage variation control unit, for a determination of whether a signal processing circuit is normal or abnormal.

Abstract: A pressure sensor includes a sensor chip and a resin portion. The sensor chip extends in a lengthwise direction and includes a membrane whose length in a thickness direction perpendicular to the lengthwise direction is smaller than another part, and a piezoelectric element provided in the membrane. The sensor chip includes a fixed end that is covered with and fixed to the resin portion, and a free end opposite from the fixed end in the lengthwise direction. The free end is spaced away from the resin portion in the lengthwise direction, and the membrane is located in the free end. A shortest separation distance between the membrane and a part of the resin portion covering the sensor chip is equal to or larger than a length of the sensor chip along a crosswise direction of the sensor chip perpendicular to both the lengthwise direction and the thickness direction.

Abstract: A pressure sensor includes a sensor chip and a resin portion. The sensor chip extends in a lengthwise direction and includes a membrane whose length in a thickness direction perpendicular to the lengthwise direction is smaller than another part, and a piezoelectric element provided in the membrane. The sensor chip includes a fixed end that is covered with and fixed to the resin portion, and a free end opposite from the fixed end in the lengthwise direction. The free end is spaced away from the resin portion in the lengthwise direction, and the membrane is located in the free end. A shortest separation distance between the membrane and a part of the resin portion covering the sensor chip is equal to or larger than a length of the sensor chip along a crosswise direction of the sensor chip perpendicular to both the lengthwise direction and the thickness direction.

Abstract: A physical quantity detector includes: a bridge circuit portion that includes a bridge circuit including a first, second, third, and fourth strain gauges each having a resistance value that changes in response to an application of a physical quantity and to temperature, the bridge circuit portion outputting, as a first detection signal, a first voltage, and outputting, as a second detection signal, a second voltage; a temperature characteristic adjustment portion that is connected in parallel to the bridge circuit portion, and outputs, as a third detection signal, a third voltage corresponding to the input voltage; a first signal processing circuit portion that receives the first and second detection signals, and outputs a first differential voltage; and a second signal processing circuit portion that receives the second and third detection signals, and outputs a second differential voltage.

Abstract: A pressure sensor includes: a first substrate having first and second diaphragms on one surface provided by first and second recesses on another surface; first and second detecting elements on the first and second diaphragms; a second substrate providing a first reference pressure chamber with the one surface of the first substrate; a third substrate providing a second reference pressure chamber sealing the second recess; and a calculator calculating an offset value by a difference between a reference signal and an inspection signal and detecting a pressure of a measurement medium by a difference between a detection signal and the offset value. The first detecting element outputs the detection signal or the inspection signal according to a pressure difference between a first reference pressure or a reference medium pressure and a measurement medium pressure in the first recess.

Abstract: A physical quantity detector includes: a bridge circuit portion that includes a bridge circuit including a first, second, third, and fourth strain gauges each having a resistance value that changes in response to an application of a physical quantity and to temperature, the bridge circuit portion outputting, as a first detection signal, a first voltage, and outputting, as a second detection signal, a second voltage; a temperature characteristic adjustment portion that is connected in parallel to the bridge circuit portion, and outputs, as a third detection signal, a third voltage corresponding to the input voltage; a first signal processing circuit portion that receives the first and second detection signals, and outputs a first differential voltage; and a second signal processing circuit portion that receives the second and third detection signals, and outputs a second differential voltage.

Abstract: A pressure sensor includes: a first substrate having first and second diaphragms on one surface provided by first and second recesses on another surface; first and second detecting elements on the first and second diaphragms; a second substrate providing a first reference pressure chamber with the one surface of the first substrate; a third substrate providing a second reference pressure chamber sealing the second recess; and a calculator calculating an offset by a difference between reference and inspection signals and detecting the pressure of the measurement medium by a difference between the detection signal and the offset value. The first detecting element outputs the detection or inspection signal according to pressure difference between the first reference pressure and reference medium pressure or measurement medium pressure in the first recess. The second detecting element outputs the reference signal according to a difference between the first and second reference pressure.