Texas Instruments Corporation

Jeffrey B Parfenchuck

David M Jones

David Alexander Gammie

Jerry Doorenbos

R Mark Stitt, Ii

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.

Current leakage compensation circuit and method

A temperature-compensated monolithic logarithmic amplifier includes a logarithmic amplifier cell ( ) configured to produce a logarithmic voltage signal (V ) representative of a difference between a first voltage (V ) developed across a first PN junction device (D ) in response to an input signal (I ) and a second voltage (V ) developed across a second PN junction device (D ) in response to a reference signal (I ) and an output circuit ( ) including an output amplifier ( ), a temperature-dependent first resistive element (R ) having a positive temperature coefficient, and a second resistive element (R ). The output circuit ( ) produces a temperature-compensated output signal (V ) in response to the logarithmic voltage signal (V ). The first resistive element (R ) is composed of conductive aluminum or aluminum alloy interconnection metallization that also is utilized as interconnection metallization throughout the monolithic logarithmic amplifier.

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Tucson, AZ, United States of America

Jeffrey B Parfenchuck