Mks Instruments, Inc.

Philip J Maiorana

Santhi E Mathew

Donald K Smith

Stephen F Horne

Claudia Quigley

Leonid Mindlin

Eric R Taranto

A system and method are described for maintaining power dissipation substantially constant across the sensor interface board of a capacitance pressure transducer. A shorted diaphragm level detector detects a shorting of the diaphragm onto one or more reference electrodes. A power dissipating resistor is placed near the oscillator that drives the capacitance detecting circuit in the capacitance pressure transducer. The resistor is switched across a power supply when the shorting is detected, causing current to flow through the resistor so that power can be added in an amount sufficient to maintain power dissipation by the oscillator substantially constant when the diaphragm shorts.

Constant power dissipation in capacitance pressure transducers

A compensated sensor includes a sensor, a relatively fast feedthrough path, and a relatively slow compensation path. The relatively fast feedthrough path includes a summer and output circuitry, such as a summing amplifier. The relatively slow compensation path includes circuitry that produces one or more correction factors for such sensor deficiencies as temperature dependency, or nonlinearity effects, for example. These one or more correction factors are fed to the summer for summing with the uncompensated sensor output. Additionally, the output of the output circuitry (e.g., summing amplifier), is fed back to the compensation circuitry where it is compared to a compensated sensor output developed by the compensation circuitry. The difference between the compensated sensor signal developed in the compensation circuitry and the output signal fed back to the compensation circuitry is also provided to the summer for summing with the one or more correction factors and the uncompensated sensor output.

Apparatus and method for compensated sensor output

Growing community of inventors

Cambridge, MA, United States of America

Philip J Maiorana