US 8,893,556 B2Granted

Pressure sensor

AssigneeTransducers Direct LLC

InventorDavid Allen Topmiller

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Abstract

A pressure sensor is claimed for measuring the pressure of a fluid. The pressure sensor comprises two or more half bridges, an analog-to-digital converter, a microcontroller, an output generator, and one or more redundancy circuits. Each half bridge comprises two resistive pressure sensing elements (RSPE) electrically coupled to the analog-to-digital converter. Each redundancy circuit comprises a switch and resistor electrically in series. A redundancy circuit may be disposed electrically in parallel with any or all of the RSPEs of the half bridges such that when an RSPE fails open, its corresponding redundancy circuit may be activated in order to permit the resistor of the redundancy circuit to take the place of the RSPE. This permits the analog-to-digital converter to continue to operate normally, even with a failed RSPE. The pressure sensor may then base its calculated pressure on the remaining half bridges which do not have a failed RSPE.

Claims20

Dependent claims

A pressure sensor for measuring the pressure of a fluid, the pressure sensor comprising two or more half bridges, an analog-to-digital converter, a microcontroller, an output generator, and one or more redundancy circuits, wherein:

the two or more half bridges are mechanically coupled to the fluid;
each of the two or more half bridges comprises a first resistive pressure sensing element (RPSE) and a second RPSE, such that the resistance of the first RPSE increases when the pressure of the fluid increases, and the resistance of the second RPSE decreases when the pressure of the fluid increases;
the analog-to-digital converter is electrically coupled to the two or more half bridges and is operable to measure the resistance of the first and second RPSEs of the two or more half bridges such that the analog-to-digital converter is operable to produce a first digital number corresponding to the pressure of the fluid based on the measured resistance of the first and second RPSEs of at least one of the two or more half bridges;
the microcontroller is electrically coupled to the analog-to-digital converter and the output generator, such that the microcontroller is operable to read the first digital number from the analog-to-digital converter, generate a second digital number corresponding to the pressure of the fluid, and write the second digital number to the output generator;
the output generator is operable to receive the second digital number from the microcontroller and produce an electrical output signal based on the second digital number such that the electrical output signal corresponds to the pressure of the fluid;
and
the one or more redundancy circuits are electrically coupled to the one or more of the first RPSEs or one or more of the second RPSEs of the two or more half bridges, and the redundancy circuit comprises a resistor and a switch in series, wherein:
the switch is electrically coupled to the microcontroller and comprises an open position and a closed position such that the microcontroller determines whether the switch is in the open position or the closed position;
and
when the switch is in the open position, the resistor has little or no effect on the resistance of the one or more first RPSEs or the one or more second RPSEs with which the redundancy circuit is electrically in parallel;
and when the switch is in the closed position, the resistor is electrically in parallel with the one or more first RPSEs or the one or more second RPSEs with which the redundancy circuit is electrically in parallel.

8 more elements

A method for operating a pressure sensor for measuring the pressure of a fluid, wherein the pressure sensor comprises two or more half bridges, an analog-to-digital converter, a microcontroller, an output generator, and one or more redundancy circuits, wherein:

the two or more half bridges are mechanically coupled to the fluid;
each of the two or more half bridges comprises a first resistive pressure sensing element (RPSE) and a second RPSE, such that the resistance of the first RPSE increases when the pressure of the fluid increases, and the resistance of the second RPSE decreases when the pressure of the fluid increases;
the analog-to-digital converter is electrically coupled to the two or more half bridges and is operable to measure the resistance of the first and second RPSEs of the two or more half bridges such that the analog-to-digital converter is operable to produce a first digital number corresponding to the pressure of the fluid based on the measured resistance of the first and second RPSEs of at least one of the two or more half bridges;
the microcontroller is electrically coupled to the analog-to-digital converter and the output generator, such that the microcontroller is operable to read the first digital number from the analog-to-digital converter, generate a second digital number corresponding to the pressure of the fluid, and write the second digital number to the output generator;
the output generator is operable to receive the second digital number from the microcontroller and produce an electrical output signal based on the second digital number such that the electrical output signal corresponds to the pressure of the fluid;
and
the one or more redundancy circuits are electrically coupled to the one or more of the first RPSEs or one or more of the second RPSEs of the two or more half bridges, and the redundancy circuit comprises a resistor and a switch in series, wherein:
the switch is electrically coupled to the microcontroller and comprises an open position and a closed position such that the microcontroller determines whether the switch is in the open position or the closed position;
and
when the switch is in the open position, the resistor has little or no effect on the resistance of the one or more first RPSEs or the one or more second RPSEs with which the redundancy circuit is electrically in parallel;
and when the switch is in the closed position, the resistor is electrically in parallel with the one or more first RPSEs or the one or more second RPSEs with which the redundancy circuit is electrically in parallel, and the method comprises:
determining that one or more of the first or second RPSEs has malfunctioned;
setting to the closed position the switch of the redundancy circuit electrically in parallel with the malfunctioned first or second RPSE;
and
basing the measured pressure on the resistance of the one or more half bridges which do not have a malfunctioned first or second RPSE.

12 more elements

Dependencies are inferred from the claim text.