Transconductance amplifier circuitry
AssigneeApple Inc.
InventorsJohn J. Parkes, Jr., Krzysztof Babinski
Life of this patent
Estimating the term…
Abstract
A digital to analog converter (DAC) can include a current mode DAC to receive an OC word from digital logic indicating an amount of current to add to or remove from sources of respective transistors of an amplifier and generate a current based on the OC word, an active output stage including a positive current mirror and a negative current mirror to generate a positive current and a negative current based on at least a portion of the generated current, and a plurality of outputs including a plurality of sink outputs and a plurality of source outputs to provide the positive and negative currents to the sources of the respective transistors.
Claims20
A digital to analog converter (DAC), comprising:
- a current mode DAC to receive an offset correction (OC) digital word from digital logic indicating an amount of current to add to or remove from sources of respective transistors of an amplifier and generate a current based on the OC digital word;
- an active output stage including a positive current mirror and a negative current mirror to generate a positive current and a negative current based on at least a portion of the generated current;
- and
- a plurality of outputs including a plurality of sink outputs and a plurality of source outputs to provide the positive and negative currents to the sources of the respective transistors.
A system comprising:
- an amplifier comprising:
- a first pair of transistors, including a first transistor and a second transistor, electrically coupled to a first input of a differential input;
- and
- a second pair of transistors, including a third transistor and a fourth transistor, electrically coupled to a second input of the differential input;
- and
- a DAC comprising:
- a current mode DAC electrically coupled to receive an offset correction (OC) digital word from digital logic indicating an amount of current to sink from or source to the first and second pairs of transistors and generate a current based on a subset of the OC digital word;
- an active output stage to generate a positive current and a negative current based on at least a portion of the generated current;
- and
- a plurality of outputs including a plurality of sink outputs and a plurality of source outputs, the plurality of sink outputs including a first sink output and a second sink output electrically coupled to sources of and sink current from the first and third transistors, respectively, and a plurality of source outputs including a first source output and a second source output electrically coupled to sources of and source current to the second and fourth transistors, respectively.
A method of direct current (DC) offset correction (OC) comprising:
- receiving, at a current mode digital to analog converter (DAC) of a DCOC DAC and from digital logic, an OC digital word indicating an amount of current to source to or sink from sources of respective transistors of an amplifier;
- generating, by the current mode DAC, a current based on the OC digital word;
- generating, by an active output stage including a positive current mirror and a negative current mirror, a positive current and a negative current based on at least a portion of the generated current;
- and
- providing, by a plurality of outputs of the DCOC DAC including a plurality of sink outputs and a plurality of source outputs, the positive and negative currents to the sources of the respective transistors.
Dependencies are inferred from the claim text.