Integrated pyroelectric sensor and method

Abstract

An integrated circuit pyroelectric sensor includes two MOSFETS coupled in a differential amplifier configuration, each MOSFET having a common source. A pyroelectric capacitor is coupled to the gate of a respective one of the MOSFET. A polysilicon filament is disposed between the pyroelectric capacitors which acts as a heating element when a current is passed therethrough. The voltage difference between the drain of each MOSFET is thus a function of the voltage difference between the pyroelectric capacitors. One of the pyroelectric capacitors is disposed at the leading edge of the sensor with respect to the direction of a fluid flow. The fluid flow across the sensor will cause the first capacitor to have a different temperature than the other capacitor of the trailing edge of the sensor whose temperature is a function of the temperature of the heating element. As the temperature of each pyroelectric capacitor changes, the amount of charge stored by each pyroelectric capacitor changes, thereby developing a differential voltage across the gates, and hence, the drains, of the integrated MOSFETS. Since the charge stored and voltage across each pyroelectric capacitor is a function of temperature, the differential voltage between the drains of each MOSFET is a function of temperature.

Dependencies are inferred from the claim text.