Microelectromechanical capacitive pressure sensor having a valve portion being operable to close first output and open second output to equalize pressure

A MEMS pressure sensor apparatus, comprising:

• a sensor portion comprising a deformable membrane and a first volume, and
• a valve portion comprising a first output to a first side of the pressure sensor and a second output to a second side of the pressure sensor, wherein the valve portion is operable to:
• close the second output and open the first output to equalize pressure in the first volume with pressure at the first side of the pressure sensor for calibrating the pressure sensor;
• and
• close the first output and open the second output to equalize pressure in the first volume with pressure at the second side of the pressure sensor for pressure measurement,
• wherein the valve portion comprises a second volume connected to the first volume, a first membrane comprising the first output, a second membrane comprising at least part of the second output, and a third membrane positioned in the second volume and between the first membrane and the second membrane, wherein the third membrane is adjustable to close the first output for the pressure measurement and the third membrane is adjustable to close the second output for offset nulling.

A MEMS pressure sensor apparatus, comprising:

• a sensor portion comprising a deformable membrane and a first volume, and
• a valve portion comprising a first output to a first side of the pressure sensor and a second output to a second side of the pressure sensor, wherein the valve portion is operable to:
• close the second output and open the first output to equalize pressure in the first volume with pressure at the first side of the pressure sensor for calibrating the pressure sensor;
• and
• close the first output and open the second output to equalize pressure in the first volume with pressure at the second side of the pressure sensor for pressure measurement,
• wherein the pressure sensor is a capacitive pressure sensor and comprises a first electrode in the first volume, a second electrode forming or comprising the deformable membrane, and a third electrode, wherein the electrodes are electrically insulated from each other, the second electrode is positioned between the first electrode and the third electrode, and the third electrode is configured to let the pressure at the first side of the pressure sensor to affect the deformable membrane.