Abstract: A sensor for determining at least one parameter with a sigma-delta converter (1) comprises switched input capacitors and feedback capacitors (Cf1, Cf2, Crefc1, Crefc2, Creff1, Creff2, Crt1, Crt2, Cr1, Cr2, Ctemp1, Ctemp2, Cs1, Cs2). At least one of the capacitors is designed such that its capacitance depends on the parameter to be determined. In this way, the change of capacitance can be directly determined by means of the sigma-delta converter. Due to a symmetric design of the converter a higher accuracy can be reached.

Abstract: To measure the flow in a liquid, the liquid (1) is led in a duct (2) along a flow sensor (3). The flow sensor (3) is integrated together with a processing and control circuit on a semiconductor substrate. It comprises a heating and, symmetrically thereto, two temperature sensors. The flow is determined from the temperature difference between the temperature sensors and/or from the power dissipation of the heating. For calibrating the sensor, a valve (4) is provided by means of which the duct (2) can be interrupted. This arrangement allows a flow measurement of high accuracy.

Abstract: The A/D-converter with optional analog preprocessing comprises two analog inputs (I1, I2), wherein a converter (1, 2) is connected to each input for generating a first and a second digital value (D1, D2) respectively. These are fed to a table (3) for generating a lookup value (D). A decimation filter (4) processes several such lookup values and generates an output value (O). With this arrangement the table can be kept comparatively small while it is still possible to reach high resolution and precision. The A/D-converter is especially suited for applications where two or more analog signals have to be combined and digitized.

Abstract: The A/D-converter with optional analog preprocessing comprises two analog inputs (I1, I2), wherein a converter (1, 2) is connected to each input for generating a first and a second digital value (D1, D2) respectively. These are fed to a table (3) for generating a lookup value (D). A decimation filter (4) processes several such lookup values and generates an output value (O). With this arrangement the table can be kept comparatively small while it is still possible to reach high resolution and precision. The A/D-converter is especially suited for applications where two or more analog signals have to be combined and digitized.

Abstract: To measure the flow in a liquid, the liquid (1) is led in a duct (2) along a flow sensor (3). The flow sensor (3) is integrated together with a processing and control circuit on a semiconductor substrate. It comprises a heating and, symmetrically thereto, two temperature sensors. The flow is determined from the temperature difference between the temperature sensors and/or from the power dissipation of the heating. For calibrating the sensor, a valve (4) is provided by means of which the duct (2) can be interrupted. This arrangement allows a flow measurement of high accuracy.

Abstract: A sensor for determining at least one parameter with a sigma-delta converter (1) comprises switched input capacitors and feedback capacitors (Cf1, Cf2, Crefc1, Crefc2, Creff1, Creff2, Crt1, Crt2, Cr1, Cr2, Ctemp1, Ctemp2, Cs1, Cs2). At least one of the capacitors is designed such that its capacitance depends on the parameter to be determined. In this way, the change of capacitance can be directly determined by means of the sigma-delta converter. Due to a symmetric design of the converter a higher accuracy can be reached.