Capacitance sensing circuit for membrane pressure sensor
First Claim
1. A capacitance sensing circuit for a membrane pressure sensor, the sensing circuit comprising a controller, two switches, in signal communication with the controller, a charge amplifier and a charge injector, the charge amplifier is connected to the switches via a sensor capacitor Cs and a reference capacitor Cr, the sensor and reference capacitors are arranged in parallel with one another and a parasitic capacitance Cp to ground, the charge injector and amplifier are arranged in parallel connection between the capacitors and the controller, the controller is configured to determine a charge imbalance indicative of a pressure difference between membranes of the pressure sensor.
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Abstract
A capacitance sensing circuit for a membrane pressure sensor is provided. The sensing circuit has a controller, two switches in signal communication with the controller, a charge amplifier and a charge injector. The charge amplifier is connected to the switches via a sensor capacitor Cs and a reference capacitor Cr. The sensor and reference capacitors are arranged in parallel with one another and a parasitic capacitance Cp to ground. The charge injector and amplifier are arranged in parallel connection between the capacitors and the controller. The controller is configured to determine a charge imbalance indicative of a pressure difference between membranes of the pressure sensor.
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Citations
8 Claims
- 1. A capacitance sensing circuit for a membrane pressure sensor, the sensing circuit comprising a controller, two switches, in signal communication with the controller, a charge amplifier and a charge injector, the charge amplifier is connected to the switches via a sensor capacitor Cs and a reference capacitor Cr, the sensor and reference capacitors are arranged in parallel with one another and a parasitic capacitance Cp to ground, the charge injector and amplifier are arranged in parallel connection between the capacitors and the controller, the controller is configured to determine a charge imbalance indicative of a pressure difference between membranes of the pressure sensor.
Specification