Interface circuit of capacitive accelerometer sensor

Abstract

The invention relates to an interface circuit (5) for a capacitive acceleration sensor (3) for measuring an acceleration value sensed by the sensor (3). The interface circuit (5) includes a plurality of electrical switches (S1‑S7) and three programmable capacitors (Cf, Cref, Cp). Two of the programmable capacitors (Cf, Cref) are arranged to enable gain adjustment of the interface circuit (5), while one of the programmable capacitors (Cp) is arranged to enable acceleration range selection.

Description

technical field [0001] The present invention relates to an interface circuit for a capacitive accelerometer sensor for converting the charge received from the capacitive accelerometer sensor into a useful signal for a given application. The invention also relates to a method for operating an interface circuit. Background technique [0002] A capacitive accelerometer is an accelerometer device that measures acceleration (on a surface) using capacitive sensing techniques. It senses and records acceleration on a device or device and converts this acceleration into current or voltage. Capacitive accelerometers are also sometimes called vibration sensors. They include capacitive microelectromechanical system (MEMS) elements that function as capacitive accelerometer sensors connected to electronic circuits (also known as interface circuits). When fed by an electronic circuit, the MEMS element converts the force due to its acceleration into an electrical signal, which in turn is...

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Problems solved by technology

It is a disadvantage that no means are provided to implement the feedback capacitor to achieve the programmability requirements for both gain magnitude and range adjustment

[0018] Patent application US 2015 / 0280668A1 describes a capacitive programmable gain amplifier, but does not provide means for easily adjusting the gain size and range adjustment at the same time, which is a disadvantage of it

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