Sensors for measuring temperature, pressure transducers including temperature sensors and related assemblies and methods

Abstract

Quartz resonator pressure transducers for use in subterranean boreholes include a quartz pressure sensor and an electronic temperature sensor. Temperature sensors include a constant current generator, a proportional to absolute temperature (PTAT) current generator, and a relaxation oscillator. Pressure transducers may include such a temperature sensor. Methods of monitoring pressure in a subterranean borehole may include monitoring a frequency output of a quartz pressure sensor and monitoring a frequency output of an electronic temperature sensor.

1 . A quartz resonator pressure transducer for use in a subterranean borehole, comprising:
 a pressure housing comprising at least one chamber;   an electronics housing comprising an electronics assembly;   a quartz pressure sensor in communication with the at least one chamber and for measuring pressure of a fluid disposed within the at least one chamber, wherein the electronics assembly is configured to drive the quartz pressure sensor at a selected frequency and to sense a pressure-related frequency response from the quartz pressure sensor; and   an electronic temperature sensor electrically coupled to the electronics assembly and configured to output a temperature signal to the electronics assembly.   
     
     
         2 . The quartz resonator pressure transducer of  claim 1 , wherein the temperature signal comprises a frequency signal. 
     
     
         3 . The quartz resonator pressure transducer of  claim 1 , wherein the electronic temperature sensor comprises a silicon temperature sensor. 
     
     
         4 . The quartz resonator pressure transducer of  claim 3 , wherein the electronic temperature sensor comprises a proportional to absolute temperature (PTAT) current generator configured to generate a PTAT current. 
     
     
         5 . The quartz resonator pressure transducer of  claim 4 , wherein the electronic temperature sensor further comprises a constant current generator configured to generate a constant current. 
     
     
         6 . The quartz resonator pressure transducer of  claim 5 , wherein the electronic temperature sensor comprises a relaxation oscillator that is coupled to each of the PTAT current generator and the constant current generator, the relaxation oscillator configured to generate an output signal responsive to a complementary to absolute temperature current comprising a difference between the constant current and the PTAT current. 
     
     
         7 . The quartz resonator pressure transducer of  claim 5 , wherein the electronic temperature sensor has a trip point for charging and discharging a capacitor, the trip point responsive to the constant current. 
     
     
         8 . The quartz resonator pressure transducer of  claim 1 , further comprising a pressure bulkhead for separating the pressure housing from the electronics housing, wherein the electronic temperature sensor is at least partially embedded in the pressure bulkhead. 
     
     
         9 . The quartz resonator pressure transducer of  claim 1 , wherein both the quartz pressure sensor and the electronic temperature sensor are positioned to be at least partially disposed within the fluid disposed within the at least one chamber. 
     
     
         10 . The quartz resonator pressure transducer of  claim 1 , wherein the electronic temperature sensor is disposed in the electronics housing. 
     
     
         11 . The quartz resonator pressure transducer of  claim 10 , wherein the electronic temperature sensor is disposed on an integrated circuit of the electronics assembly in the electronics housing. 
     
     
         12 . The quartz resonator pressure transducer of  claim 10 , further comprising a quartz reference sensor positioned between the electronic temperature sensor and the quartz pressure sensor. 
     
     
         13 . The quartz resonator pressure transducer of  claim 1 , further comprising:
 a quartz reference sensor; and   a pressure bulkhead for separating the pressure housing from the electronics housing, wherein the electronic temperature sensor is positioned between the quartz reference sensor and the quartz pressure sensor.   
     
     
         14 . The quartz resonator pressure transducer of  claim 13 , wherein the electronic temperature sensor and the quartz reference sensor are positioned on a first side of the pressure bulkhead and the quartz pressure sensor is positioned on a second side of the pressure bulkhead opposing the first side. 
     
     
         15 . The quartz resonator pressure transducer of  claim 14 , wherein the electronic temperature sensor and the quartz reference sensor are each disposed in a transistor outline (TO) package. 
     
     
         16 . The quartz resonator pressure transducer of  claim 15 , wherein the transistor outline (TO) package of the electronic temperature sensor has a volume that is less than a volume of the transistor outline (TO) package of the quartz reference sensor. 
     
     
         17 . The quartz resonator pressure transducer of  claim 13 , wherein the quartz reference sensor is positioned on a first side of the pressure bulkhead and the quartz pressure sensor and the electronic temperature sensor are positioned on a second side of the pressure bulkhead opposing the first side. 
     
     
         18 . A temperature sensor, comprising:
 a constant current generator configured to generate a constant current (I CONST );   a proportional to absolute temperature (PTAT) current generator configured to generate a PTAT current; and   a relaxation oscillator operably coupled to the constant current generator and the PTAT current generator, and configured to charge and discharge a capacitor responsive to a complementary to absolute temperature current comprising a difference between the constant current and the PTAT current.   
     
     
         19 . The temperature sensor of  claim 18 , wherein the relaxation oscillator includes a comparator having a first input and a second input, the first input configured to receive a voltage on the capacitor, and the second input configured to receive a trip voltage. 
     
     
         20 . The temperature sensor of  claim 19 , wherein the relaxation oscillator is configured such that:
 during a first phase of the relaxation oscillator, the constant current sources current to the capacitor and the PTAT current sinks current from the capacitor; and   during a second phase of the relaxation oscillator, the PTAT current sources current to the capacitor and the constant current sinks current from the capacitor.   
     
     
         21 . The temperature sensor of  claim 19 , wherein relaxation oscillator is configured to raise the trip voltage during a first phase of the relaxation oscillator, and lower the trip voltage during a second phase of the relaxation oscillator. 
     
     
         22 . A pressure transducer, comprising:
 at least one pressure sensor; and   the temperature sensor of  claim 18 .   
     
     
         23 . A method of monitoring pressure in a subterranean borehole, comprising:
 resonating a quartz pressure sensor under an applied fluid pressure at at least one frequency with an electronics assembly of a pressure transducer;   monitoring a frequency output of the quartz pressure sensor with the electronics assembly;   resonating a quartz reference sensor at at least one frequency with the electronics assembly;   monitoring a frequency output of the quartz reference sensor with the electronics assembly;   powering an electronic temperature sensor with the electronics assembly; and   monitoring a frequency output of the electronic temperature sensor with the electronics assembly.   
     
     
         24 . The method of  claim 23 , further comprising measuring a temperature within the pressure transducer with a proportional to absolute temperature (PTAT) sensor. 
     
     
         25 . The method of  claim 23 , further comprising temperature-compensating the monitored frequency output of the quartz pressure sensor with the electronics assembly using the frequency output of the electronic temperature sensor.