Texas Instruments Corporation

David Alexander Gammie

Jerry Doorenbos

Jeffrey B Parfenchuck

Jeffery B Parfenchuck

Sergey V Alenin

David M Jones

Edward Mullins

An amplifier circuit includes first (A) and second (B) operational amplifiers connected in a parallel configuration. A first terminal () of a first input resistor () is coupled to one input of both of the first (A) and second (B) amplifiers. A first terminal () of a second input resistor () is coupled to another input of both of the first (A) and second (B) amplifiers. A differential input voltage is applied between the second terminals of the first and second input resistors. The output signals of the first (A) and second (B) operational amplifiers are combined to produce an output signal (AB) representative of feedback currents produced in the first () and second () input resistors. Upper and lower common mode input voltage ranges associated with the differential input voltage extend substantially above and below the upper and lower supply voltages, respectively, of the amplifier circuit.

Current shunt instrumentation amplifier with extended bipolar input common mode range

An amplifier circuit includes first (A) and second (B) operational amplifiers connected in a generally parallel configuration, each with inputs coupled through the same pair of matched input resistors which receive a differential input signal that may have both a positive and negative common mode range. An offset adjustment amplifier () receives a differential error signal representative of the difference between offset voltages of the first and second operational amplifiers and generates offset adjustment signals that are applied to input stages of the first and second operational amplifiers to adjust their respective offset voltages so as to equalize them. With the offset voltages equalized, the first and second operational amplifiers operate seamlessly as a common mode component of the differential input signal undergoes a transition from its positive to its negative range, so as to avoid inaccuracies and abrupt changes in an output voltage during the transition, the output voltage being produced in response to outputs of both first and second operational amplifiers.

Amplifier switching control circuit and method for current shunt instrumentation amplifier having extended position and negative input common mode range

A base current compensation circuit is configured for injecting base current to the base of a transistor device to compensate for the lost current demanded by a transistor base. The base current compensation circuit is configured to inject current into the base of the transistor without the headroom requirements, as well as being less complex than other approaches. An exemplary base current compensation circuit comprises a sampling circuit and a current mirror feedback circuit configured for providing multiples of the base current demanded by the transistor device.

Method and circuit for base current compensation

The present invention overcomes the disadvantages of the prior art and provides a new temperature compensation trimming technique. Temperature compensated output is provided in a logarithmic voltage output device by the steps of: measuring the resistance of a first resistor, a second resistor, and a third resistor at a first temperature; measuring again the resistances of the first resistor, second resistor, and third resistor at a second temperature; and trimming the drift of the third resistor according to a calculated temperature compensation trim.

Temperature compensation trim method

A leakage compensation circuit and technique is provided that compensates for losses in a referenced current of an amplifier circuit due to leakage elements. The leakage compensation circuit is configured to inject current substantially equal in magnitude to the leakage current into one or more junctions of the amplifier circuit to compensate for lost referenced current due to leakage. As a result, the amplifier circuit and various devices can realize the flow of the reference current as substantially intended without detrimental effects of leakage current, thus maintaining the integrity of the referenced current. The leakage compensation circuit comprises an array of compensation regions configured to approximate the collective loss that is created by the leakage elements and provide a compensation current substantially equal in magnitude to one or more junctions to compensate for lost referenced current.

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Tucson, AZ, United States of America

David Alexander Gammie