Method and circuit for trimming offset and temperature drift for operational amplifiers and voltage references

A device trimming method comprising the steps of:

• trimming a first current source having a first temperature coefficient and trimming a second current source having a second temperature coefficient to cause the current from the first current source to be equal to the current from the second current source, wherein the first and second current sources comprise a combination current source, and wherein this trimming step occurs at a first temperature;
• performing a first offset trim at the first temperature, wherein the first offset trim is performed by connecting combination current sources to at least one of a first offset-control terminal and a second offset-control terminal;
• and
• performing a second offset trim at a second temperature, wherein the second offset trim is performed by changing the temperature dependency of at least one of the combination current sources, wherein the changing of the temperature dependency of the combination current source is performed by changing the temperature coefficient of a second current source to be equal to the temperature coefficient of a first current source.

A device trimming method comprising the steps of:

• trimming a first current source having a first temperature coefficient and trimming a second current source having a second temperature coefficient to cause the current from the first current source to be equal to the current from the second current source, and wherein this trimming step occurs at a first temperature;
• connecting the first current source to one of a first offset-control terminal and a second offset-control terminal and connecting the second current source to one of the first offset-control terminal and the second offset-control terminal to perform a first offset trim at the first temperature;
• and
• changing the temperature dependency of the first current source by replacing the first current source with a third current source having the same temperature coefficient as the temperature coefficient of the second current source to perform a second offset trim at a second temperature.

A trimming circuit comprising:

• an input stage configured with at least one offset-control terminal;
• and
• a current source stage configured to trim the at least one offset-control terminal, wherein the current source stage comprises a first and second current source;
• wherein at least one of the first and second current sources are configured for trimming such that the current from the first current source is equal to the current from the second current source;
• wherein at least one of the first and second current sources are configured to be selectively coupled to the at least one offset-control terminal for trimming the trimming circuit;
• wherein the first current source is configured to have a first temperature coefficient and the second current source is configured to have a second temperature coefficient which is different from the first temperature coefficient, and wherein the first current source is configured to be replaceable with a third current source having a temperature coefficient equal to the second temperature coefficient.

A trimming circuit comprising:

• an input stage configured with at least one offset-control terminal;
• and
• a current source stage configured to trim the at least one offset-control terminal, wherein the current source stage comprises a combination current source which comprises a first and second current source;
• wherein at least one of the first and second current sources are configured for trimming such that the current from the first current source is equal to the current from the second current source;
• wherein the combination current source is configured to be selectively coupled to the at least one offset-control terminal for trimming the trimming circuit;
• wherein the first current source is configured to have a first temperature coefficient and the second current source is configured to have a second temperature coefficient which is different from the first temperature coefficient, and wherein the first current source is configured to be replaceable with a third current source having a temperature coefficient equal to the second temperature coefficient.