Communications: electrical – Condition responsive indicating system – With particular system function
Reexamination Certificate
2001-06-15
2003-02-11
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
With particular system function
C340S540000, C340S551000, C340S653000, C340S657000, C340S661000, C340S663000, C340S664000
Reexamination Certificate
active
06518880
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a physical-quantity detection sensor such as a pressure sensor. This invention also relates to a physical-quantity detection apparatus. This invention further relates to a sensor-signal processing apparatus.
2. Description of the Related Art
U.S. Pat. No. 6,040,779 discloses monitoring of the function of a symmetrical sensor bridge circuit which is performed in that the signal from the positive or negative half-bridge is subtracted from half the bridge supply voltage in a summing member and is subsequently amplified by an amplifier in such a way that it corresponds to the full bridge signal. The full bridge signal is compared with the amplified difference signal in a comparator. If the difference signal deviates in an unacceptable manner from the full bridge signal, the comparator switches an alarm signal on the output signal of the sensor so that this output signal is placed into a range which lies outside of the normal operational range of the sensor.
PCT application publication number WO 96/22515 discloses a semiconductor pressure transducer which comprises a silicon die having a topside and a bottom side. The silicon die further has a cavity in the bottom side, thereby forming a diaphragm. Four piezoresistive elements are disposed on the topside of the silicon die on a periphery of the diaphragm and connected via metalized conductors disposed on the silicon die in the form of a Wheatstone bridge. A plurality of bonding pads disposed on the topside of the silicon die provides external access to the Wheatstone bridge circuit. A diagnostic conductor is disposed on the topside of the silicon die such that the periphery of the diaphragm is crossed, the diagnostic conductor being connected to corresponding bonding pads at each of the diagnostic conductor. Thus, when the diaphragm ruptures, the diagnostic conductor ruptures thereby providing a positive indication of the rupture of the diaphragm by external circuitry in which the diagnostic conductor is used.
Japanese patent application publication number 2000-146991 corresponding to European patent application EP 0962748 A1 discloses monitoring of the function of a sensor component. The monitoring in Japanese application 2000-146991 is of an extended version designed to identify a change of ambient conditions and to timely take a countermeasure against an operation stop. In Japanese application 2000-146991, a sensor component is formed in a monolithic integral circuit, and has a sensor and at least one measurement amplifier. The sensor component is provided with external terminals for at least the feed of a current and an output measurement signal. Furthermore, an evaluation circuit is provided in the sensor component, and is connected to at least a circuit internal measurement point. The evaluation circuit is connected to a modulator for modulating at least one of a fed current, a fed voltage, and the output measurement signal. A diagnosis signal generated from circuit internal measurement values is fed out from an existing external connection terminal in the sensor component.
Japanese patent application publication number 10-506718 corresponding to PCT application publication number WO 97/05464 discloses a sensor having a diaphragm. In the sensor of Japanese application 10-506718, first and second resistance measurement bridges are placed on first and second half areas of the diaphragm, respectively. Two bridge signals generated by the first and second resistance measurement bridges are compared to check the function of the sensor and to detect a malfunction of the sensor.
Japanese patent application publication number 61-155931 discloses a pressure sensor including a first diaphragm and a second diaphragm. The first diaphragm supports a sensor member, and can deform in response to a pressure to be detected. The first diaphragm defines a reference pressure chamber. The second diaphragm supports a checking sensor member for generating a signal corresponding to a leakage from the reference chamber. The second diaphragm separates the reference pressure chamber from a checking pressure chamber. The checking sensor member is placed in the reference pressure chamber.
Japanese patent application publication number 8-247881 discloses a pressure difference sensor with a diagnosis function. In the sensor of Japanese application 8-247881, a bridge is composed of gauge resistors whose resistances vary in response to a distortion depending on a pressure to be detected. An energizing power supply is connected with the bridge. Two signals which appear at respective legs of the bridge are added into an addition result signal. The addition result signal is compared with a threshold level. When the addition result signal exceeds the threshold level, it is diagnosed that the sensor is abnormal.
Japanese patent application publication number 62-95485 discloses an apparatus designed so that an abnormality-indicating signal is outputted to an external when operation of a sensor is wrong. The apparatus of Japanese application 62-95485 includes a sensor power supply and a sensor portion which are connected to each other via a power feed line and an output signal line. The sensor portion has a carrier generation circuit and a carrier superimposing circuit. The carrier generation circuit acts to generate a radio-frequency signal (a carrier). The carrier generation circuit is activated and deactivated in response to whether or not a sensor circuit is normal. The carrier superimposing circuit operates to superimpose the radio-frequency signal (the carrier) on electric power supplied along the power feed line. The sensor power supply has a carrier sensing circuit for detecting the presence and absence of the carrier superimposed on the electric power supplied along the power feed line. The carrier sensing circuit outputs a signal to an external which indicates whether or not the sensor is normal.
Japanese patent application publication number 10-300615 discloses an on-line self diagnosis on a semiconductor pressure sensor including a diaphragm. In Japanese application 10-300615, the sensor is designed to output two signals. The two output signals from the sensor are inputted into a microcomputer on a time sharing basis, and are processed thereby. The signal processing by the microcomputer is designed to detect a damage to the diaphragm, a damage to a sensor connector, ageing-based variations in the conditions of a sensing portion and a circuit portion of the sensor, an ageing-based variation in the sensor sensitivity, and a variation in the zero point of the sensor.
Japanese patent application publication number 3-210047 discloses a sensor abnormality diagnosis apparatus. In the apparatus of Japanese application 3-210047, a sensor uses a power supply voltage as a reference voltage, and a pull-up resistor is subjected to the power supply voltage. The pull-up resistor may be replaced by a pull-down resistor connected to the ground. A current driven into the sensor is changed by varying the resistance of the pull-up resistor or the pull-down resistor. Detection is made as to a quantity of a variation in an output voltage from the sensor which occurs when the current driven into the resistor is changed. The detected variation quantity is compared with a reference variation quantity represented by data stored in a memory. The reference variation quantity is available when the sensor is normal. When the detected variation quantity is greater than the reference variation quantity, the sensor is diagnosed as being abnormal.
Japanese patent application publication number 9-304427 discloses a physical-quantity detecting apparatus which includes an acceleration sensor having a sensing portion and a diagnosing portion. The sensing portion detects an acceleration as a physical quantity, and outputs a signal depending on the detected acceleration. The diagnosing portion implements a diagnosing process of deciding whether the sensing portion is normal or abnormal in response to the output si
Denso Corporation
Law Offices of David G. Posz
Previl Daniel
Wu Daniel J.
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