Abstract: A heater is disclosed for use with pressure transducers. The disclosed heater includes a first heating element and a second heating element. The first heating element is characterized by a first electrical resistance. The second heating element is characterized by a second electrical resistance. In preferred embodiments, the first electrical resistance is different than the second electrical resistance. The disclosed heater can be used to accurately heat a pressure transducer to at least four different operating temperatures by selectively (a) connecting the first heating element to the transducer temperature control circuitry, (b) connecting the second heating element to the transducer temperature control circuitry, (c) connecting the first and second heating elements in series with the transducer temperature control circuitry, or (d) connecting the first and second heating elements in parallel with the transducer temperature control circuitry.

Abstract: A pressure transducer has an output characterized by two or more slopes. A pressure transducer generates an first output signal that may be linearly proportional to the sensed pressure. The pressure transducer includes an electrical circuit that shapes the first output signal to produce a shaped output signal that according to a first function of the first output signal when the first output signal is less than the first value and according to a second function of the first output signal when the first output signal is greater than a second value. Preferably, the shaped output signal is a dual slope signal such that the shaped output signal has a first linear portion characterized by a first slope and a second linear portion characterized by a second slope. The two linear portions of the shaped output signal may intersect at a knee point which corresponds to a pressure between two preferred desired pressure ranges.

Abstract: A capacitive pressure sensor includes a chamber coupled to a region whose pressure is to be determined. The sensor includes a conductive flexible diaphragm and a pair of electrodes, each defining a capacitance with the diaphragm. Variations in pressure in the chamber cause deflection of the diaphragm which in turn causes variation in the capacitances. A processing circuit applies an excitation signal to the capacitances and couples the capacitances to inductive elements. A current through the inductive elements is detected to determine the difference in the sensor capacitances and, therefore, the deflection of the diaphragm and the pressure in the chamber.