Monolithic differential pair thermocouple amplifier
View Patent ↗Two Silicon Carbide negative positive negative transistors realized on a monolithic substrate as a differential pair to keep their base-emitter junctions at nearly the same temperature such that their kT/q sensitivities tract together with their base connections electrically connected to the cold junction terminals of a thermocouple to create an amplified differential voltage across output load resistors while operating at high temperature.
1. A monolithic substrate differential pair the amplifier apparatus for use with a thermocouple including a thermocouple hot junction with a hot junction minus output and a hot junction positive output, and a thermocouple cold junction with a cold junction minus output and a cold junction positive output, comprising:
a first mounting substrate;
the thermocouple hot junction mounted on the first mounting substrate;
a ceramic isolation base mounted to the first mounting substrate;
the thermocouple cold junction mounted to the ceramic isolation base;
a silicon carbide monolithic substrate mounted to the ceramic isolation base; and
a differential pair circuit with a first silicon carbide negative positive negative transistor and a second silicon carbide negative positive negative transistor mounted in thermal sensitive proximity on the monolithic substrate.
2. The apparatus of claim 1 , the differential pair circuit further comprising:
direct current power connection and a direct current ground connection on the ceramic isolation base.
3. The apparatus of claim 2 , the differential pair circuit further comprising:
the first silicon carbide negative positive negative transistor including a first base, a first collector, and a first emitter;
the second silicon carbide negative positive negative transistor including a second base, a second collector, and a second emitter.
4. The apparatus of claim 3 , the differential pair circuit further comprising:
the first collector connected to a first collector resistor to direct current power; and
the second collector connected to a second collector resistor to direct current power.
5. The apparatus of claim 3 , the differential pair circuit further comprising:
the first emitter connected to direct current ground; and
the second emitter connected to direct current ground.
6. The apparatus of claim 3 , the differential pair circuit further comprising:
a first base capacitor connected from the first base to direct current ground.
7. The apparatus of claim 6 , the differential pair circuit further comprising:
a second base capacitor connected from the second base to direct current ground.
8. The apparatus of claim 3 , the differential pair circuit further comprising:
an input capacitor connected between direct current power and direct current ground.