Measuring device for capacitive pressure measurement
First Claim
1. A measuring device for capacitive pressure and/or temperature measurement for tire pressure control systems, the measuring device comprising:
- at least one sensor, which has a measuring element for detecting a state value that is applied at an output-side measuring node of the measuring element;
at least one A/D converter operating according to a dual-slope method;
a charging/discharging circuit for charging and discharging the measuring element and for generating a sawtooth-shaped measuring potential at the measuring node as a measure for a capacitance of the measuring element;
a period counter, which determines the periods of the measuring potential; and
a clock counter, which determines cycles of a clock signal that lie within a duration of at least one period of the measuring potential.
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Accused Products
Abstract
A measuring device is disclosed for capacitive pressure and/or temperature measurement, particularly for tire pressure control systems, having at least one sensor, which has a capacitive measuring element to detect a state value, which is applied at an output-side measuring node of the measuring element, with at least one A/D converter operating according to the dual-slope method, with a charging/discharging circuit, for mutual charging and discharging of the measuring element and for generating a sawtooth-shaped measuring potential at the measuring node as a measure for the capacitance of the measuring element, with a period counter, which determines the periods of the measuring potential, and with a clock counter, which determines the cycles of a clock signal, which lie within the duration of at least one period of the measuring potential. The invention relates to a measuring method for capacitive pressure and/or temperature measurement.
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Citations
19 Claims
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1. A measuring device for capacitive pressure and/or temperature measurement for tire pressure control systems, the measuring device comprising:
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at least one sensor, which has a measuring element for detecting a state value that is applied at an output-side measuring node of the measuring element;
at least one A/D converter operating according to a dual-slope method;
a charging/discharging circuit for charging and discharging the measuring element and for generating a sawtooth-shaped measuring potential at the measuring node as a measure for a capacitance of the measuring element;
a period counter, which determines the periods of the measuring potential; and
a clock counter, which determines cycles of a clock signal that lie within a duration of at least one period of the measuring potential. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 19)
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14. A measuring method for capacitive pressure measurement for tire pressure control systems, the method comprising the steps of:
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repeatedly measuring a measuring potential of a capacitive element; and
averaging an uncorrelated noise, which occurs due to an exceeding or falling of the measuring potential above an upper reference threshold or below a lower reference threshold, respectively. - View Dependent Claims (15, 16, 17, 18)
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Specification