# US 10,768,018 B2 · Sensing apparatus having switch resistance compensation circuit and associated methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,018 B2 - Document ID: US10768018B2 - Status: Granted - Kind: B2 - Application number: 15/778,390 - Filed: 2016-11-21 - Published: 2018-12-06 - Granted: 2020-09-08 - Earliest claimed: 2015-11-30 - Assignees: Nokia Technologies Oy - Applicants: Nokia Technologies Oy - Inventors: Michael Astley - Web page: https://patentgrep.com/patent/US10768018B2 ## CPC - G01D 5/16: by varying resistance - G01J 1/44: Electric circuits {(for command of an exposure part G03B7/02)} - G01J 5/20: using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices - G01J 5/22: Electrical features thereof - G01R 33/0041: {using feed-back or modulation techniques} - G01R 33/09: Magnetoresistive devices - G06F 3/045: using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact - G11C 7/14: Dummy cell management; Sense reference voltage generators - G11C 13/0023: {Address circuits or decoders} - G11C 13/003: {Cell access} - G11C 13/0033: {Disturbance prevention or evaluation; Refreshing of disturbed memory data} - G11C 13/004: {Reading or sensing circuits or methods} - H03K 17/9643: {using a plurality of detectors, e.g. keyboard} - G01J 2005/202: {Arrays} - G11C 2213/77: Array wherein the memory element being directly connected to the bit lines and word lines without any access device being used - 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 - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G11C: STATIC STORES (semiconductor memory devices H10B) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract An apparatus comprising: a passive array (202) of resistive elements (250); a row selector switch (204) and a column selector switch (206) configured to respectively connect a particular row and a particular column of resistive elements to ground; and a feedback column selector switch (208) configured to connect all columns of resistive elements to a voltage source, except for the particular column connected to ground by the column selector switch; the voltage source configured to apply a voltage to the columns of resistive elements, the voltage matching a voltage dropped over the resistive element connected in circuit by the row and column selector switches; and further comprising: a row selector switch compensation circuit (220), a column selector switch compensation circuit (240) and/or a feedback column selector switch compensation circuit (260) each configured to apply a voltage across a corresponding dummy element equal and opposite to a voltage dropped over the corresponding selector switch. ## Claims ### Claim 1 An apparatus comprising: a passive array of resistive elements; a row selector switch configured to connect a current source to a row of resistive elements of the passive array; a column selector switch configured to connect a column of resistive elements of the passive array to ground, wherein the row selector switch and column selector switch select a resistive element in the passive array; and a feedback column selector switch configured to connect one or more columns of resistive elements to a voltage source, except for the column connected to ground by the column selector switch; the voltage source configured to apply a voltage to the one or more columns of resistive elements connected to the voltage source, the voltage matching a voltage dropped over the resistive element connected in a circuit formed in part by the row selector switch and column selector switch; and one or more of: a row selector switch compensation circuit configured to apply a voltage across a row dummy element equal and opposite to a voltage dropped over the row selector switch; a column selector switch compensation circuit configured to apply a voltage across a column dummy element equal and opposite to a voltage dropped over the column selector switch; or a feedback column selector switch compensation circuit configured to apply a voltage across a feedback column dummy element equal and opposite to a voltage dropped over the feedback column selector switch. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the apparatus comprises each of the row selector switch compensation circuit, the column selector switch compensation circuit and the feedback column selector switch compensation circuit. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the dummy element in one or more of the row selector switch compensation circuit, the column selector switch compensation circuit or the feedback column selector switch compensation circuit is a dummy switch configured to have comparable physical properties to the corresponding selector switch. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the apparatus comprises a current source configured to provide a current to the circuit; and wherein the row selector switch compensation circuit comprises a current sink configured to provide an equal and opposite current to the current source. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the column selector switch compensation circuit comprises: an operational amplifier configured to apply a voltage across the column dummy element according to the current passing through the column connected to ground. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the column selector switch compensation circuit comprises: a first resistor connected in parallel with the operational amplifier; and a second resistor connected between an input terminal of the operational amplifier and ground; wherein: the ratio of the resistance of the first resistor to the resistance of the second resistor is one. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the feedback column selector switch compensation circuit comprises: an operational amplifier configured to apply a voltage across the feedback column dummy element according to the average current passing through all the columns of resistive elements connected to the voltage source except for the column connected to ground by the column selector switch. ### Claim 8 (depends on 5) The apparatus of claim 5, wherein the feedback column selector switch compensation circuit comprises: a resistor connected in parallel with the operational amplifier; and a second resistor connected to an input terminal of the operational amplifier; wherein: a ratio of the resistance of the first resistor to the resistance of the second resistor corresponds to the number of columns of resistive elements minus one. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the passive array of resistive elements comprises one or more of: a sensor; a photodetector; an X-ray detector; a memristor; a piezoresistive (pressure/strain) sensor; a magneto-resistive sensor; a resistive temperature sensor (thermistor); a light dependent sensor; a resistive level sensor; a field-effect-transistor based sensor; a graphene-based sensor; a chemical sensor, or a biosensor. ### Claim 10 A method comprising using an apparatus to detect a sensing event at a resistive element in a passive array of an apparatus, the apparatus comprising: a row selector switch configured to connect a current source to a row of resistive elements of the passive array; a column selector switch configured to connect a column of resistive elements of the passive array to ground, wherein the row selector switch and column selector switch select a resistive element in the passive array; and a feedback column selector switch configured to connect all columns of resistive elements to a voltage source, except for the column connected to ground by the column selector switch; the voltage source configured to apply a voltage to the one or more columns of resistive elements connected to the voltage source, the voltage matching a voltage dropped over the resistive element connected in a circuit formed in part by the row selector switch and column selector switch; and further comprising one or more of: a row selector switch compensation circuit configured to apply a voltage across a row dummy element equal and opposite to a voltage dropped over the row selector switch; a column selector switch compensation circuit configured to apply a voltage across a column dummy element equal and opposite to a voltage dropped over the column selector switch; or a feedback column selector switch compensation circuit configured to apply a voltage across a feedback column dummy element equal and opposite to a voltage dropped over the feedback column selector switch. ### Claim 11 (depends on 10) The method of claim 10, wherein the apparatus comprises each of the row selector switch compensation circuit, the column selector switch compensation circuit and the feedback column selector switch compensation circuit. ### Claim 12 (depends on 10) The method of claim 10, wherein the dummy element in one or more of the row selector switch compensation circuit, the column selector switch compensation circuit or the feedback column selector switch compensation circuit is a dummy switch configured to have comparable physical properties to the corresponding selector switch. ### Claim 13 (depends on 10) The method of claim 10, wherein the apparatus comprises a current source configured to provide a current to the circuit; and wherein the row selector switch compensation circuit comprises a current sink configured to provide an equal and opposite current to the current source. ### Claim 14 (depends on 10) The method of claim 10, wherein the column selector switch compensation circuit comprises: an operational amplifier configured to apply a voltage across the column dummy element according to the current passing through the column connected to ground. ### Claim 15 (depends on 14) The method of claim 14, wherein the column selector switch compensation circuit comprises: a first resistor connected in parallel with the operational amplifier; and a second resistor connected between an input terminal of the operational amplifier and ground; wherein: the ratio of the resistance of the first resistor to the resistance of the second resistor is one. ### Claim 16 (depends on 10) The method of claim 10, wherein the feedback column selector switch compensation circuit comprises: an operational amplifier configured to apply a voltage across the feedback column dummy element according to the average current passing through all the columns of resistive elements connected to the voltage source except for the column connected to ground by the column selector switch. ### Claim 17 (depends on 14) The method of claim 14, wherein the feedback column selector switch compensation circuit comprises: a resistor connected in parallel with the operational amplifier; and a second resistor connected to an input terminal of the operational amplifier; wherein: a ratio of the resistance of the first resistor to the resistance of the second resistor corresponds to the number of columns of resistive elements minus one. ### Claim 18 (depends on 10) The method of claim 10, wherein the passive array of resistive elements comprises one or more of: a sensor; a photodetector; an X-ray detector; a memristor; a piezoresistive (pressure/strain) sensor; a magneto-resistive sensor; a resistive temperature sensor (thermistor); a light dependent sensor; a resistive level sensor; a field-effect-transistor based sensor; a graphene-based sensor; a chemical sensor, or a biosensor. ### Claim 19 A computer readable medium comprising computer program code stored thereon, the computer readable medium and computer program code being configured to, when run on at least one processor, control the operation of an apparatus, the apparatus comprising: a passive array of resistive elements; a row selector switch configured to connect a current source to a row of resistive elements of the passive array; a column selector switch configured to connect a column of resistive elements of the passive array to ground, wherein the row selector switch and column selector switch select a resistive element in the passive array; and a feedback column selector switch configured to connect all columns of resistive elements to a voltage source, except for the column connected to ground by the column selector switch; the voltage source configured to apply a voltage to the one or more columns of resistive elements connected to the voltage source, the voltage matching a voltage dropped over the resistive element connected in a circuit formed in part by the row selector switch and column selector switch; and further comprising one or more of: a row selector switch compensation circuit configured to apply a voltage across a row dummy element equal and opposite to a voltage dropped over the row selector switch; a column selector switch compensation circuit configured to apply a voltage across a column dummy element equal and opposite to a voltage dropped over the column selector switch; or a feedback column selector switch compensation circuit configured to apply a voltage across a feedback column dummy element equal and opposite to a voltage dropped over the feedback column selector switch; the control providing for: detecting a sensing event at a resistive element in the passive array by switching the one or more of the row selector switch compensation circuit, the column selector switch compensation circuit and the feedback column selector switch compensation circuit.