# US 2012/0074972 A1 · Sensor self-diagnostics using multiple signal paths > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0074972 A1 - Document ID: US20120074972A1 - Status: Published application - Kind: A1 - Application number: 12/889,749 - Filed: 2010-09-24 - Published: 2012-03-29 - Earliest claimed: 2010-09-24 - Assignees: Infineon Technologies AG - Inventors: Friedrich Rasbornig; Mario Motz; Dirk Hammerschmidt; Ferdinand Gastinger; Bernhard Schaffer; Wolfgang Granig - Web page: https://patentgrep.com/patent/US20120074972A1 ## CPC - B60T 8/885: {using electrical circuitry} - G01D 3/08: with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown - B60T 2250/06: Sensor zero-point adjustment; Offset compensation - B60T 2270/406: Test-mode; Self-diagnosis - B60T 2270/411: Offset failure - B60T 2270/413: Plausibility monitoring, cross check, redundancy - G01R 31/007: {using microprocessors or computers} - G01R 31/2644: {Adaptations of individual semiconductor devices to facilitate the testing thereof} - G01R 31/2829: {Testing of circuits in sensor or actuator systems (testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844)} - G01R 31/2856: {Internal circuit aspects, e.g. built-in test features; Test chips; Measuring material aspects, e.g. electro migration [EM]} - G01R 31/2884: {using dedicated test connectors, test elements or test circuits on the IC under test (G01R31/2855 takes precedence)} - G01R 31/3187: Built-in tests - H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu} - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Embodiments relate to systems and methods for sensor self-diagnostics using multiple signal paths. In an embodiment, the sensors are magnetic field sensors, and the systems and/or methods are configured to meet or exceed relevant safety or other industry standards, such as SIL standards. For example, a monolithic integrated circuit sensor system implemented on a single semiconductor ship can include a first sensor device having a first signal path for a first sensor signal on a semiconductor chip; and a second sensor device having a second signal path for a second sensor signal on the semiconductor chip, the second signal path distinct from the first signal path, wherein a comparison of the first signal path signal and the second signal path signal provides a sensor system self-test. ## Claims ### Claim 1 A monolithic integrated circuit sensor system comprising: a first sensor device having a first signal path for a first sensor signal on a semiconductor chip; and a second sensor device having a second signal path for a second sensor signal on the semiconductor chip, the second signal path distinct from the first signal path, wherein a comparison of the first signal path signal and the second signal path signal provides a sensor system self-test. ### Claim 2 (depends on 1) The sensor system of claim 1, further comprising a digital signal processor (DSP) on the semiconductor chip and coupled to the first and second signal paths to receive the first and second signal path signals, wherein the comparison is implemented by the DSP. ### Claim 3 (depends on 2) The sensor system of claim 2, wherein the DSP comprises at least one of a first software block associated with the first signal path and a second software block associated with the second signal path, or a first digital signal processing portion associated with the first signal path and a second digital signal processing portion associated with the second signal path. ### Claim 4 (depends on 2) The sensor system of claim 2, wherein the DSP is coupled to the first and second signal paths by an analog-to-digital (A/D) conversion channel cross-switching device. ### Claim 5 (depends on 1) The sensor system of claim 1, further comprising at least one additional sensor device coupled to the second signal path to provide a comparison signal. ### Claim 6 (depends on 5) The sensor system of claim 5, wherein the at least one additional sensor device is selected from the group consisting of a temperature sensor, a stress sensor, a current sensor, a voltage sensor and a magnetic field sensor. ### Claim 7 (depends on 5) The sensor system of claim 5, further comprising a multiplexer on the semiconductor chip and coupling the second sensor device and the at least one additional sensor device to the second signal path. ### Claim 8 (depends on 1) The sensor system of claim 1, wherein the first and second sensor devices comprise magnetic field sensors. ### Claim 9 (depends on 1) The sensor system of claim 1, wherein the first signal path comprises a first analog-to-digital (A/D) converter and the second signal path comprises a second A/D converter different from the first A/D converter. ### Claim 10 (depends on 9) The sensor system of claim 9, wherein the first A/D converter operates with at least one working principle distinct from a working principle of the second A/D converter. ### Claim 11 (depends on 1) The sensor system of claim 1, further comprising a first biasing circuit coupled to the first sensor device and the first signal path, and a second biasing circuit coupled to the second sensor device and the second signal path. ### Claim 12 (depends on 11) The sensor system of claim 11, further comprising a biasing comparator configured to receive a signal from the first biasing circuit and a signal from the second biasing circuit and to compare the signals. ### Claim 13 (depends on 1) The sensor system of claim 1, wherein the first signal path, when compared with the second signal path, has at least one characteristic selected from the group consisting of being faster, being more precise, having less noise and having a different working principle. ### Claim 14 (depends on 1) The sensor system of claim 1, wherein the sensor system meets a Safety Integrity Level (SIL) standard. ### Claim 15 A method of providing a self-test in a monolithic integrated circuit sensor system comprising: implementing, on a single semiconductor chip, a main signal path comprising a main sensor; implementing, on the single semiconductor chip, a secondary sensor and a secondary signal path, the secondary signal path distinct from the main signal path and, when compared with the main signal path, having at least one characteristic selected from the group consisting of being slower, being less precise, having more noise and having a different working principle; and conducting a self-test of the sensor system by comparing a signal of the main signal path with a signal of the secondary signal path. ### Claim 16 (depends on 15) The method of claim 15, further comprising multiplexing at least one additional sensor to the secondary signal path. ### Claim 17 (depends on 16) The method of claim 16, further comprising receiving at least one compensation signal from the at least one additional sensor. ### Claim 18 (depends on 15) The method of claim 15, further comprising: implementing a first analog-to-digital (A/D) conversion technique on the main signal path; and implementing a second A/D conversion technique on the secondary signal path, the second A/D conversion technique different from the main A/D conversion technique. ### Claim 19 (depends on 15) The method of claim 15, further comprising: biasing the main sensor by a first biasing portion; biasing the secondary sensor by a second biasing portion different from the first biasing portion; and measuring a biasing current of the main sensor and a biasing current of the secondary sensor. ### Claim 20 (depends on 15) The method of claim 15, further comprising: coupling the main and secondary signal paths to a digital signal processor (DSP); processing the signal of the main signal path using a first software portion of the DSP; and processing the signal of the secondary signal path using a second software portion of the DSP, the second software portion different from the first software portion. ### Claim 21 (depends on 20) The method of claim 20, further comprising providing parallel outputs of the DSP comprising a main signal path portion and a secondary signal path portion. ### Claim 22 (depends on 15) The method of claim 15, wherein comparing comprises forming at least one of a quotient or a linear transformation of the signal of the main signal path and the signal of the secondary signal path. ### Claim 23 (depends on 22) The method of claim 22, further comprising evaluating the at least one quotient or linear transformation to detect a system failure. ### Claim 24 (depends on 15) The method of claim 15, further comprising adjusting a measurement range of at least one of the main sensor or the secondary sensor. ### Claim 25 (depends on 15) The method of claim 15, further comprising exchanging the main sensor and the secondary sensor such that the main sensor is coupled to the secondary signal path and the secondary sensor is coupled to the main signal path.