Circuit element pair matching method and circuit

A circuit in which a pair of composite circuit elements may be configured to match, comprising:

• N circuit elements designed to match;
• switches configurable after fabrication, according to M different combinations, to connect N/2 of the N circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N circuit elements to form a second composite circuit element of the pair;
• and
• control logic, configured to:
• sequentially in time, for each combination of the M combinations:
• configure the switches to form the first and second composite circuit elements according to the combination;
• and
• measure a characteristic of the circuit that includes the formed first and second composite circuit elements, wherein the characteristic is indicative of how well the formed first and second composite circuit elements match;
• choose a final combination of the M combinations whose measured characteristic indicates a best match;
• and
• configure the switches to form the first and second composite circuit elements according to the final combination;
• wherein to measure the characteristic of the circuit, the control logic:
• spectrally separates error induced by mismatch of the first and second composite circuit elements formed by the combination from mismatch-induced error of other pairs of elements of the circuit;
• and
• measures the error induced by mismatch of the first and second composite circuit elements at an output of the circuit.

A method for matching a pair of composite circuit elements included in a circuit, comprising:

• fabricating N circuit elements designed to match;
• fabricating switches configurable after fabrication, according to M different combinations, to connect N/2 of the N circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N circuit elements to form a second composite circuit element of the pair;
• sequentially in time, for each combination of the M combinations:
• configuring the switches to form the first and second composite circuit elements according to the combination;
• and
• measuring a characteristic of the circuit that includes the formed first and second composite circuit elements, wherein the characteristic is indicative of how well the formed first and second composite circuit elements match;
• choosing a final combination of the M combinations whose measured characteristic indicates a best match;
• configuring the switches to form the first and second composite circuit elements according to the final combination;
• wherein said choosing the final combination of the M combinations whose measured characteristic indicates the best match is performed during a calibration phase that occurs after reset of the circuit and prior to operating the circuit in a mission mode;
• and
• during the mission mode:
• using the switches to chop the first and second composite circuit elements formed by the final combination;
• and
• de-chopping an output of the circuit.

A circuit in which a pair of composite circuit elements may be configured to match, comprising:

• N circuit elements designed to match;
• switches configurable after fabrication, according to M different combinations, to connect N/2 of the N circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N circuit elements to form a second composite circuit element of the pair;
• and
• control logic, configured to:
• sequentially in time, for each combination of the M combinations:
• configure the switches to form the first and second composite circuit elements according to the combination;
• and
• measure a characteristic of the circuit that includes the formed first and second composite circuit elements, wherein the characteristic is indicative of how well the formed first and second composite circuit elements match;
• choose a final combination of the M combinations whose measured characteristic indicates a best match;
• and
• configure the switches to form the first and second composite circuit elements according to the final combination;
• wherein the control logic chooses the final combination of the M combinations whose measured characteristic indicates the best match during a calibration phase that occurs after reset of the circuit and prior to operating the circuit in a mission mode;
• and
• wherein the control logic is further configured to, during the mission mode, use the switches to chop the first and second composite circuit elements formed by the final combination, while an output of the circuit is de-chopped.

A method for matching a pair of composite circuit elements included in a circuit, comprising:

• fabricating N circuit elements designed to match;
• fabricating switches configurable after fabrication, according to M different combinations, to connect N/2 of the N circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N circuit elements to form a second composite circuit element of the pair;
• sequentially in time, for each combination of the M combinations:
• configuring the switches to form the first and second composite circuit elements according to the combination;
• and
• measuring a characteristic of the circuit that includes the formed first and second composite circuit elements, wherein the characteristic is indicative of how well the formed first and second composite circuit elements match;
• choosing a final combination of the M combinations whose measured characteristic indicates a best match;
• configuring the switches to form the first and second composite circuit elements according to the final combination;
• and
• fabricating D circuit elements in addition to the N circuit elements, wherein the D circuit elements are designed to match the N circuit elements;
• wherein the switches are configurable after fabrication, according to M+E different combinations, to connect N/2 of the N+D circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N+D circuit elements to form a second composite circuit element of the pair, wherein E is a positive integer;
• wherein said configuring the switches and said measuring the characteristic of the circuit are performed for each combination of the M+E combinations;
• and
• wherein said choosing the final combination is of the M+E combinations whose measured characteristic indicates a best match.

A circuit in which a pair of composite circuit elements may be configured to match, comprising:

• N circuit elements designed to match;
• switches configurable after fabrication, according to M different combinations, to connect N/2 of the N circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N circuit elements to form a second composite circuit element of the pair;
• and
• control logic, configured to:
• sequentially in time, for each combination of the M combinations:
• configure the switches to form the first and second composite circuit elements according to the combination;
• and
• measure a characteristic of the circuit that includes the formed first and second composite circuit elements, wherein the characteristic is indicative of how well the formed first and second composite circuit elements match;
• choose a final combination of the M combinations whose measured characteristic indicates a best match;
• and
• configure the switches to form the first and second composite circuit elements according to the final combination;
• and
• D circuit elements in addition to the N circuit elements, wherein the D circuit elements are designed to match the N circuit elements;
• wherein the switches are configurable after fabrication, according to M+E different combinations, to connect N/2 of the N+D circuit elements to form a first composite circuit element of the pair and to connect a remaining N/2 of the N+D circuit elements to form a second composite circuit element of the pair, wherein E is a positive integer;
• wherein the control logic configures the switches and measures the characteristic of the circuit for each combination of the M+E combinations;
• and
• wherein the control logic chooses the final combination as a combination of the M+E combinations whose measured characteristic indicates a best match.