Abstract: A notification sensor arrangement includes a drift pressure sensor measuring a drift signal indicative of a drift of a differential pressure sensor. The drift pressure sensor has a drift sensing unit formed on or in a symmetrical diaphragm, which has an upper side in fluid communication with a first fluid having a first pressure and a lower side in fluid communication with the first fluid having the first pressure. The notification sensor arrangement includes a comparing unit comparing the drift signal with a predefined threshold value to determine if the drift of the differential pressure sensor is a critical drift, a notification unit outputting a warning signal in response to a determination of the critical drift, and a base supporting the drift pressure sensor and the differential pressure sensor.

Abstract: A photoacoustic gas sensor is provided. The photoacoustic gas sensor includes a hermetically sealed housing filled with a reference gas. Further, the photoacoustic gas sensor includes a microphone system arranged inside the housing. The microphone system is configured to generate a first microphone signal comprising a first signal component related to a photoacoustic excitation of the reference gas and a second microphone signal comprising a second signal component related to the photoacoustic excitation. The photoacoustic gas sensor additionally includes a circuit configured to generate an output signal based on the first microphone signal and the second microphone signal by destructively superimposing a third signal component of the first microphone signal related to mechanical vibrations of the photoacoustic gas sensor and a fourth signal component of the second microphone signal related to the mechanical vibrations.

Abstract: A photoacoustic gas sensor is provided. The photoacoustic gas sensor includes a hermetically sealed housing filled with a reference gas. Further, the photoacoustic gas sensor includes a microphone system arranged inside the housing. The microphone system is configured to generate a first microphone signal comprising a first signal component related to a photoacoustic excitation of the reference gas and a second microphone signal comprising a second signal component related to the photoacoustic excitation. The photoacoustic gas sensor additionally includes a circuit configured to generate an output signal based on the first microphone signal and the second microphone signal by destructively superimposing a third signal component of the first microphone signal related to mechanical vibrations of the photoacoustic gas sensor and a fourth signal component of the second microphone signal related to the mechanical vibrations.

Abstract: An infra-red (IR) device comprising a dielectric membrane formed on a silicon substrate comprising an etched portion; and at least one patterned layer formed within or on the dielectric membrane for controlling IR emission or IR absorption of the IR device, wherein the at least one patterned layer comprises laterally spaced structures.

Abstract: An IR source in the form of a micro-hotplate device including a CMOS metal layer made of at least one layer of embedded on a dielectric membrane supported by a silicon substrate. The device is formed in a CMOS process followed by a back etching step. The IR source also can be in the form of an array of small membranes —closely packed as a result of the use of the deep reactive ion etching technique and having better mechanical stability due to the small size of each membrane while maintaining the same total IR emission level. SOI technology can be used to allow high ambient temperature and allow the integration of a temperature sensor, preferably in the form of a diode or a bipolar transistor right below the IR source.

Abstract: An infra-red (IR) device comprising a dielectric membrane formed on a silicon substrate comprising an etched portion; and at least one patterned layer formed within or on the dielectric membrane for controlling IR emission or IR absorption of the IR device, wherein the at least one patterned layer comprises laterally spaced structures.

Abstract: An IR detector in the form of a thermopile including one or more thermocouples on a dielectric membrane supported by a silicon substrate. Each thermocouple is composed of two materials, at least one of which is p-doped or n-doped single crystal silicon. The device is formed in an SOI process. The device is advantageous as the use of single crystal silicon reduces the noise in the output signal, allows higher reproducibility of the geometrical and physical properties of the layer and in addition, the use of an SOI process allows a temperature sensor, as well as circuitry to be fabricated on the same chip. The detector can also have an IR filter wafer bonded onto it and/or have arrays of thermopiles to increase the sensitivity. The devices can also be integrated with an IR source on the same silicon chip and packaged to form a complete and miniaturised NDIR sensor.

Abstract: An IR source in the form of a micro-hotplate device including a CMOS metal layer made of at least one layer of embedded on a dielectric membrane supported by a silicon substrate. The device is formed in a CMOS process followed by a back etching step. The IR source also can be in the form of an array of small membranes—closely packed as a result of the use of the deep reactive ion etching technique and having better mechanical stability due to the small size of each membrane while maintaining the same total IR emission level. SOI technology can be used to allow high ambient temperature and allow the integration of a temperature sensor, preferably in the form of a diode or a bipolar transistor right below the IR source.

Abstract: A voltage reference circuit includes storage, programming, and test floating gate transistors. The floating gates of the storage and programming transistors are shorted, while the floating and control gates of the test transistor are shorted. The test and storage transistors are connected between an input terminal and the inputs of a comparator, with the control gate of the test transistor also being connected to the input terminal. A reference voltage is programmed by applying the reference voltage to the input terminal and increasing the net positive charge on the floating gate of the storage transistor (via the programming transistor) until its source voltage matches the source voltage of the test transistor. Then, any test voltage at the input terminal can be compared to the programmed reference voltage by comparing the source voltages of the test and storage transistors.