Complementary Current Reusing Preamp for Operational Amplifier
AssigneeTexas Instruments Incorporated
InventorTien-Ling Hsieh
Life of this patent
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Abstract
An apparatus includes a preamplifier stage to receive a power supply voltage and generate an output based upon an input. In particular, the preamplifier stage includes a biasing device coupled between the output and a ground node to bias a DC voltage level of the output independently of the power supply voltage. The preamplifier stage also includes a complementary circuit to receive the input and generate the output. The complementary circuit reuses a current through the preamplifier stage to provide an increased transconductance of the preamplifier stage for a given current level.
Claims16
An apparatus comprising:
- a preamplifier stage including:
- an output;
- a current source;
- a PMOS differential pair coupled to a power supply side of the preamplifier stage, sources of the PMOS differential pair being coupled to the current source;
- an NMOS differential pair coupled to a ground side of the preamplifier stage, drains of the NMOS differential pair being coupled to respective drains of the PMOS differential pair at the output;
- and
- a biasing device coupled between the output and a ground node.
A method comprising:
- receiving, by a preamplifier stage, a power supply voltage and a differential input;
- generating, by the preamplifier stage, an output based upon the differential input;
- biasing a DC voltage level of the output independently of the power supply voltage;
- and
- reusing, by a complimentary circuit, a current through the preamplifier stage, the complementary circuit including a PMOS differential pair coupled to a power supply side of the preamplifier stage, and an NMOS differential pair coupled to a ground side of the preamplifier stage, drains of the NMOS differential pair being coupled to respective drains of the PMOS differential pair at an output node of the preamplifier stage, sources of the PMOS differential pair being coupled to a current source.
Dependencies are inferred from the claim text.