Conexant Systems, Inc.

Yusuf Cetin

Graham Stuart Hamilton

Ibrahim Yayla

Alan T Asbeck

A novel method and apparatus for conditioning an analog signal before it is input to a downstream device such as a delta-sigma analog-to-digital converter is disclosed. An analog conditioning circuit having a reference voltage generator circuit, positive and negative voltage comparators, threshold voltage generator circuits, and a plurality of transistor gate switch limiters is disclosed. The reference voltage generator circuit generates predetermined threshold voltages against which the input signal is compared by the voltage comparators. All conditioning circuit components between the conditioning circuit input and output are electrically disconnected from the circuit when the input signal voltage does not exceed the threshold voltages, thereby minimizing signal distortion in the useful range of the input signal. When the input signal voltage meets or exceeds one of the relevant threshold voltages, the conditioning circuit components rapidly and sharply switch into the signal pathway, and the input signal is &ldquo;clipped&rdquo; appropriately. Transistor-based switches are used to provide rapid switching, and to reduce power that is consumed by the circuit when no clipping of the input signal is required. An integrated circuit including the aforementioned conditioning circuit and a delta-sigma analog-to-digital converter, and an electronic device incorporating the integrated circuit, are also disclosed.

Method and apparatus for conditioning an analog signal

An apparatus and method of calibrating a signal sourcing device having a plurality of signal sources to reduce errors between signals generated by the signal sources by categorizing the signal sources into groups based on the amount of error in the signal generated by the signal sources and selecting the signal sources from the groups in a manner which reduces the overall error in selecting signals. For example, the signal sourcing device may be a digital to analog converter having a plurality of current sources that output currents which may have an error. Such an improved digital to analog converter would categorize the current sources into groups based on the amount of error in the current generated by the current sources and selecting the current sources from the groups in a manner which reduces the overall error in selecting signals for the conversion process. The groups may include a center group that straddles the median current generated by the current sources. For example, the digital to analog converter may select current sources from complementary groups where current sources in complementary groups tend to have similar but opposite errors. This calibration method may be used to reduce errors in the signal sources which have a linear, Gaussian, or other error distributions.

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Encinitas, CA, United States of America

Yusuf Cetin