Low temperature error thermal sensor
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJaw-Juinn HORNG, Szu-Lin LIU
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Abstract
A thermal sensor in some embodiments comprises two temperature-sensitive branches, each including a thermal-sensing device, such as one or more bipolar-junction transistors, and a current source for generating a current density in the thermal-sensing device to generate a temperature-dependent signal. The thermal sensor further includes a signal processor configured to multiply the temperature-dependent signal from the branches by respective and different gain factors and combine the resultant signals to generate an output signal that is substantially proportional to the absolute temperature the thermal sensor is disposed at.
Claims20
A thermal sensor, comprising:
- a temperature-sensitive device comprising a bandgap thermal-sensing device;
- a first current source adapted to generate a current of a first value;
- a second current source adapted to generate a current of a second value different from the first value;
- a first switching device (SW1) adapted to pass the current generated by the first current source through the bandgap thermal-sensing device;
- a second switching device (SW2) adapted to pass the current generated by the second current source through the bandgap thermal-sensing device;
- the bandgap thermal-sensing device being adapted to generate a first and a second output signals responsive to temperature and the current of the first and second values, respectively;
- a third switching device (SW3);
- a gain circuit operatively connectable to the bandgap thermal-sensing device through the third switch and adapted to adjust the first or second output signal when connected to the bandgap thermal-sensing device;
- and
- a signal processing circuit operatively connected to receive the first and second output signals, and to generate an output signal based on the first and second output signals.
A method of temperature measurement, comprising:
- generating a first current density in a thermal-sensing device disposed at a temperature, T, to generate a first voltage across the thermal-sensing device;
- generating a second current density in the thermal-sensing device disposed at T, to generate a second voltage across the thermal-sensing device, the second current density being different from the first current density, wherein generating the second current density comprises connecting a gain circuit to the thermal-sensing device to adjust the second voltage relative to the second voltage without the gain circuit;
- obtaining a differential voltage, dV, between a voltage corresponding to the first voltage and a voltage corresponding to the second voltage;
- and
- determining T based on the differential voltage.
A method of temperature measurement, comprising:
- connecting a first current source to a thermal-sensing device disposed at a temperature, T, to generate a first output voltage;
- connecting a second current source and a gain circuit to the thermal-sensing device disposed at T, to generate a second output voltage, wherein the gain circuit is adapted to adjust the second output voltage relative to the second output voltage generated without the gain circuit being connected to the thermal-sensing device;
- and
- obtaining a differential voltage, dV, between a voltage corresponding to the first output voltage and a voltage corresponding to the second output voltage.
Dependencies are inferred from the claim text.