Linear transconductance amplifier
AssigneeSignetics Corporation
InventorRobert A. Blauschild
Life of this patent
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Abstract
A linear transconductance amplifier includes a differential transconductance amplifier stage and a differential correction amplifier stage. In order to achieve linear operation over a wide dynamic range, the nonlinearities generated in the transconductance amplifier stage are substantially cancelled by the nonlinearities generated in the correction amplifier stage. This is accomplished by cross-coupling the two stages and establishing the relative gain of the correction amplifier stage with respect to the transconductance amplifier stage such that the desired cancellation occurs. In a preferred embodiment, optimum cancellation occurs when the gain of the correction amplifier stage is substantially one-half the gain of the transconductance amplifier stage.
Claims15
A self-biasing linear transconductance amplifier, which comprises:
- a differential transconductance amplifier stage having a first bipolar transistor with first emitter, base and collector zones and a second bipolar transistor with second emitter, base and collector zones, said first and second base zones comprising the differential voltage input terminals of said linear transconductance amplifier and said first and second collector zones comprising the differential current output terminals of said linear transconductance amplifier;
- a differential correction amplifier stage having first and second input terminals and first and second output terminals, said first and second input terminals being directly connected, respectively, to said first and second emitter zones of said first and second bipolar transistors and said first and second output terminals being connected, respectively, to said second and first collector zones of said second and first bipolar transistors;
- and
- means for establishing the relative gain of said correction amplifier stage with respect to the gain of said transconductance amplifier stage such that the nonlinearities generated in such transconductance amplifier stage are substantially cancelled by the nonlinearities generated in said correction amplifier stage.
Dependencies are inferred from the claim text.