Patent ID: 8680920

Claim:
A reconfigurable network arrangement for use with an operational amplifier, including: an operational amplifier; a plurality of resistors and a plurality switches constructed so that the resistors can be coupled to the operational amplifier and selectively programmed so as to form a feedback path so as to selectively set the gain of the amplifier, the plurality of resistors and plurality of switches being arranged so that the resistors can be selectively connected in the feedback path in series and in parallel with each other so as to provide a selection of gain settings; a first plurality of resistors connected in series so as to provide a resistor string; a first plurality of switches constructed and arranged so that one or more junctions between resistors of the first plurality can be connected to the operational amplifier's input terminals; a second plurality of resistors; a second plurality of switches constructed and arranged so each of the second plurality of resistors can be selectively connected into the feedback path in parallel with one another; and a controller for controlling the operation of each of the switches; wherein the reconfigurable feedback path is configured to be coupled to the operational amplifier as a function of the one or more resistors of the first and second plurality connected in the feedback path; and wherein the resistor string is constructed and arranged so that it can be connected between the output of the amplifier and a reference node, and is configured as a voltage divider, wherein the state of the first plurality of switches determines where the voltage divider is tapped with respect to the feedback path arrangement; and wherein one of the resistors (R 1 ) of the resistor string can be connected between the output of the operational amplifier and the other resistors in the resistor string, such that the gain of the amplifier is defined as: A CL = R STRING + R P kR STRING = ( 1 k ) ⁢ ( R STRING + R P R STRING ) , wherein R STRING is the resistance of the sum of resistors of the first plurality of resistors that can be connected between the input and a reference node (R 2 to RN+1); k is the fraction of the total resistor Rstring that is connected between the input of the operational amplifier and the reference node for a particular gain setting; R p is the resulting resistance provided by none, one, or more of the resistors of the second plurality connected into the feedback path in parallel with the one resistor (R 1 ).