Patent ID: 6297641
Filing Date: 2001-10-02
Classification: B60N,B60R,G01L

Abstract:
A signal-processing circuit arrangement for processing at least one signal, comprising:a force sensing resistor (FSR) foil forming at least one resistive foil pressure sensor, the at least one signal indicating a status of the at least one resistive foil pressure sensor, the FSR foil including a variable foil resistor and a diode coupled in parallel with the variable foil resistor;a first switchable voltage source being a highly precise test-voltage source and providing a first current in a first flow direction through the at least one resistive foil pressure sensor, the first switchable voltage source being configured to connect to a first terminal side of the FSR foil;a second switchable voltage source providing a second current in a second flow direction through the at least one resistive foil pressure sensor, the second switchable voltage source being configured to connect to a second terminal side of the FSR foil, the first flow direction being different from the second flow direction; anda reference resistor connected in series between the second terminal side of the FSR foil and the second switchable voltage source,wherein each of the first and second currents has a respective intensity which is a function of a respective resistance value of the variable foil resistor to generate different measuring-voltage levels, the different measuring-voltage levels decreasing across the reference resistor and being detectable as measuring signals,wherein the diode is one of forward-biased and reverse-biased as a function of the first and second currents,wherein, when the first switchable voltage source is switched-on and the second switchable voltage source is switched-off, the first switchable voltage source is coupled to a ground frame via the FSR foil and via the reference resistor to determine if the FSR foil is in an OCCUPIED/NOT OCCUPIED state and if the FSR foil his a short-circuit fault, andwherein the diode is reverse-biased if the FSR foil does not have the short-circuit fault.