Enhancing dual op-amps for differential connections
AssigneeAnalog Devices, Inc.
InventorsScott A. Wurcer, Robert F. Day
Life of this patent
Estimating the term…
Abstract
In an embodiment of the invention, a differential input signal is coupled to a plurality of transconductance blocks. In some embodiments, each of the transconductance blocks divide an input transconductance among a plurality of signal paths to a plurality of outputs in each transconductance block. In an embodiment, the input transconductance may be divided based a ratio of transistor areas in the plurality of signal paths, though other embodiments may divide the transconductance differently. In some embodiments, transconductance block outputs of a plurality of transconductance blocks may be cross-coupled to provide a gain path for a differential signal than is greater than that of a common mode signal.
Claims18
An amplifier circuit comprising:
- a plurality of transconductance blocks, each transconductance block having inputs for a differential input signal and outputs for differential currents, the transconductance blocks distributing a respective transconductance gain distribution across their outputs according to a predetermined unequal distribution ratio, and
- a plurality of current mirrors, the inputs of the current mirrors coupled to the mutually interconnected outputs of the transconductance blocks and an output of each current mirror coupled to an output buffer and a capacitor;
- wherein outputs of the transconductance blocks are mutually interconnected to provide, at outputs of the amplifier circuit, a differential signal bandwidth and transconductance that is greater than a common mode bandwidth and transconductance.
A method comprising:
- coupling a differential input signal to a differential input of a plurality of transconductance blocks;
- dividing an input transconductance from the differential input signal into a plurality of transconductances;
- directing the plurality of transconductances to different outputs of the transconductance block;
- cross-coupling at least one output of each transconductance block to at least one output of another transconductance block, the cross-coupling providing a differential signal bandwidth and transconductance that is greater than a common mode bandwidth and transconductance;
- coupling the at least one output of each transconductance block coupled to the at least one output of another transconductance block to an input of a current mirror;
- and
- coupling an output of the current mirror to a capacitor and an input of an output buffer.
An amplifier circuit comprising:
- a plurality of transconductance blocks, each transconductance block including:
- inputs for a differential input signal,
- outputs for differential currents,
- a plurality of transistors with different emitter areas to distribute a transconductance gain distribution across the outputs according to a predetermined unequal distribution ratio, and
- a switchably enabled selector of at least one of the transistors having a desired emitter area in a differential signal gain path;
- wherein outputs of the transconductance blocks are mutually interconnected to provide, at outputs of the amplifier circuit, a differential signal bandwidth and transconductance that is greater than a common mode bandwidth and transconductance.
An amplifier circuit comprising:
- a plurality of transconductance blocks, each transconductance block including:
- inputs for a differential input signal,
- outputs for differential currents,
- a plurality of transistors coupled in parallel to distribute a transconductance gain distribution across the outputs according to a predetermined unequal distribution ratio, and
- a switchably enabled selector of a quantity of the transistors coupled in parallel in a differential signal gain path;
- wherein outputs of the transconductance blocks are mutually interconnected to provide, at outputs of the amplifier circuit, a differential signal bandwidth and transconductance that is greater than a common mode bandwidth and transconductance.
Dependencies are inferred from the claim text.