Class AB voltage current convertor having multiple transconductance stages and its application to power amplifiers
AssigneeBroadcom Corporation
InventorsArya Reza Behzad, Li Lin
Life of this patent
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Abstract
A Class AB voltage-to-current converter includes a primary transconductance stage, secondary transconductance stage, and a biasing circuit. The biasing circuit generates a primary bias voltage that is greater than a generated secondary bias voltage. As such, the primary transconductance stage 12 becomes active before the secondary transconductance stage 14 with respect to the magnitude of a differential input voltage 18, thereby allowing the transconductance of the secondary transconductance stage to be added (or subtracted) from the transconductance of the primary stage to improve the overall transconductance of the Class AB voltage-to-current convert.
Claims18
A class AB voltage to current converter comprises:
- primary transconductance stage operably coupled to produce a primary differential current from a differential input voltage based on a primary bias voltage;
- secondary transconductance stage operably coupled to produce a secondary differential current based on the differential input voltage and a secondary bias voltage, wherein output current of the class AB voltage current converter is a sum of the primary differential current and the secondary differential current;
- and
- biasing circuit operably coupled to produce the primary bias voltage and the secondary bias voltage, wherein the primary bias voltage is greater than the secondary bias voltage.
A linear power amplifier comprises:
- primary transconductance stage operably coupled to produce a primary differential current from a differential input voltage based on a primary bias voltage;
- secondary transconductance stage operably coupled to produce a secondary differential current based on the differential input voltage and a secondary bias voltage;
- biasing circuit operably coupled to produce the primary bias voltage and the secondary bias voltage, wherein the primary bias voltage is greater than the secondary bias voltage;
- and
- output section operably coupled to the primary transconductance stage and the secondary transconductance stage, wherein the output section sums the primary differential current and the secondary differential current to produce a differential output.
Dependencies are inferred from the claim text.