National Semiconductor Corporation

Paul Mike Henry

Gregory J Smith

Yinming Chen

A differential amplifier with adjustable offset includes a differential pair, a controller, an offset adjuster and an output stage. The differential pair and the output stage can be standard implementations such as, for example, a source-coupled PFETs and a folded-cascode output stage. The offset adjuster includes transistors that can be selectively enabled to form a composite transistor that is connected in parallel with at least one transistor of the differential pair to, in effect, increase the size of the transistor of the differential pair. The controller can reduce offset by causing the offset adjuster to increase the effective size of the appropriate transistor of the differential pair to compensate for device mismatch in the differential amplifier.

MOS differential amplifier with offset compensation

A precision voltage reference circuit for generating a constant reference voltage over a range of operating temperatures uses a bandgap voltage generator which is compensated with replicated currents fed back from the bandgap stage as control currents. These currents are attenuated and fed back in proper proportions to correct for bias conditions which would otherwise vary with temperature.

Precision voltage reference circuit with temperature compensation

An autocalibrated voltage reference includes a continuous time reference and a switched calibration reference where continuous time reference is dynamically adjusted to match the switched reference such that the temperature drift and long term drift of the continuous time reference is matched to the low temperature drift of the switched reference and further resulting in improvement of the long term drift of the switched reference and of the entire system.

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Tucson, AZ, United States of America

Paul Mike Henry