Patent ID: 6583652
Filing Date: 2003-06-24
Classification: H03F,H03H

Abstract:
A programmable transconductor for generating a differential current between first and second current output terminals responsive to a differential voltage applied between first and second voltage input terminals, comprising:a first summing node; a first feedback node; a second summing node; a second feedback node; a resistor circuit including a plurality of resistors connected in series and defining a plurality of intermediate nodes, respective ones of the plurality of intermediate nodes being located between adjacent resistors of the plurality of resistors, wherein the programmable transconductor is configured to selectively couple at least one of the plurality of resistors between the first summing node and the second summing node and to leave remaining ones of the plurality of resistors uncoupled from the first summing node and the second summing node; a switch circuit coupled between a first one of the plurality of intermediate nodes and one of: the first summing node and the second summing node; a first input circuit, coupled to the first summing node and the first voltage input terminal, the first input circuit biasing the first summing node to a suitable voltage so as to bias the first feedback node to a voltage substantially equal to a voltage applied to the first voltage input terminal; and a second input circuit, coupled to the second summing node and the second voltage input terminal, the second input circuit biasing the second summing node to a suitable voltage so as to bias the second feedback node to a voltage substantially equal to a voltage applied to the second voltage input terminal.