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1. (WO2018184638) EVALUATING CIRCUIT, SYSTEM, AND METHOD FOR EVALUATING A CAPACITIVE OR INDUCTIVE SENSOR

Pub. No.:    WO/2018/184638    International Application No.:    PCT/DE2018/200022
Publication Date: Fri Oct 12 01:59:59 CEST 2018 International Filing Date: Thu Mar 08 00:59:59 CET 2018
IPC: G01D 1/00
G01D 21/00
G01R 27/26
Applicants: CZARDYBON, Peter
CZARDYBON, Marius
Inventors: CZARDYBON, Peter
Title: EVALUATING CIRCUIT, SYSTEM, AND METHOD FOR EVALUATING A CAPACITIVE OR INDUCTIVE SENSOR
Abstract:
The invention relates to an evaluating circuit for evaluating a capacitive or inductive sensor. The evaluating circuit (1) comprises: a first and a second measurement connection point (A, B), to which sensor and/or reference elements (14, 15, 16) are connected; a charging and discharging circuit (2), which is designed to output a first charging and discharging signal to the first measurement connection point (A) and to output a second charging and discharging signal to the second measurement connection point (B); a comparator circuit (6), which compares the temporal behavior of the first charging and discharging signal and the temporal behavior of the second charging and discharging signal with each other; and an integrator circuit (7), which is connected to an output of the comparator circuit (6) and the output voltage of which changes in accordance with the voltage at the output of the comparator circuit (6). The output voltage of the integrator circuit (7) is switched to the first measurement connection point (A) in order to adjust the first charging and discharging signal or to the second measurement connection point (B) in order to adjust the second charging and discharging signal. A measurement signal at an output (10) of the evaluating circuit (1) is derived from the output voltage of the integrator circuit (7), the measurement signal being a measure of impedance deviations of the elements (14, 15, 16) at the first and second measurement connection points (A, B). The invention further relates to a system for evaluating a capacitive or inductive sensor and to a corresponding method.