Differential thermistor circuit
View Patent ↗In a general aspect, a circuit can include a first resistor configured to be coupled to a first terminal of a temperature-sensitive resistance, a second resistor configured to be coupled to a second terminal of the temperature-sensitive resistance and a temperature information circuit. The temperature information circuit can be configured to: receive a first voltage from the first terminal of the temperature-sensitive resistance; receive a second voltage from the second terminal of the temperature-sensitive resistance; and provide temperature information based on the first voltage and the second voltage. The temperature information circuit can include a first comparison circuit configured to determine a difference between the first voltage and the second voltage, and a second comparison circuit configured to compare an output of the first comparison circuit to a reference.
1. A circuit comprising:
a first resistor configured to be coupled to a first terminal of a temperature-sensitive resistance;
a second resistor configured to be coupled to a second terminal of the temperature-sensitive resistance;
a temperature information circuit configured to:
receive a first voltage from the first terminal of the temperature-sensitive resistance;
receive a second voltage from the second terminal of the temperature-sensitive resistance; and
provide temperature information based on the first voltage and the second voltage, the temperature information circuit including:
a first comparison circuit configured to determine a difference between the first voltage and the second voltage; and
a second comparison circuit configured to compare an output of the first comparison circuit to a reference.
2. The circuit of claim 1 , wherein a value of the first resistor substantially corresponds to a value of the second resistor.
3. The circuit of claim 1 , further comprising:
a voltage follower coupled to a preset voltage, the voltage follower configured to provide a bias voltage across the first resistor, the second resistor and the temperature-sensitive resistance; and
a power control circuit responsive to an enable input signal to limit power consumption of the circuit.
4. The circuit of claim 1 , wherein the first comparison circuit includes an analog-to-digital converter (ADC) configured to provide a digital information corresponding with a voltage difference between the first terminal of the temperature-sensitive resistance and the second terminal of the temperature-sensitive resistance.
5. The circuit of claim 1 , wherein the reference is a band-gap voltage.
6. The circuit of claim 5 , wherein the temperature-sensitive resistance includes at least one of a diode or a thermistor.
7. The circuit of claim 1 , wherein:
the temperature information circuit includes a reference generator configured to be coupled to a reference resistor and to provide the reference, the reference including a reference voltage;
the reference generator including:
a third resistor configured to be coupled to the first terminal of the reference resistor; and
a fourth resistor configured to be coupled to the second terminal of the reference resistor.
8. The circuit of claim 7 , wherein a value of the third resistor substantially corresponds to the value of the first resistor, and a value of the fourth resistor substantially corresponds to the value of the second resistor.
9. The circuit of claim 7 , wherein the circuit is an integrated circuit and the reference resistor includes a resistor external to the integrated circuit.
10. The circuit of claim 9 , wherein:
the temperature-sensitive resistance includes a first diode; and
the reference resistor includes a second diode.
11. A circuit comprising:
a first resistor configured to be coupled to a first terminal of a temperature-sensitive resistance;
a second resistor configured to be coupled to a second terminal of the temperature-sensitive resistance;
a temperature information circuit configured to:
receive a first voltage from the first terminal of the temperature-sensitive resistance;
receive a second voltage from the second terminal of the temperature-sensitive resistance; and
provide temperature information based on the first voltage and the second voltage, the temperature information circuit including:
a first differential comparator configured to determine a difference between the first voltage and the second voltage; and
a second differential comparator configured to compare an output of the first differential comparator to a reference voltage, the second differential comparator having an output corresponding with a temperature of the temperature-sensitive resistance.
12. The circuit of claim 11 , further comprising a voltage follower circuit coupled with the second differential comparator, the voltage follower circuit being configured to provide the reference voltage to the second differential comparator.
13. The circuit of claim 11 , wherein the temperature-sensitive resistance includes at least one of a diode or a thermistor.
14. The circuit of claim 11 , further comprising:
a voltage follower coupled to a preset voltage, the voltage follower being configured to provide a bias voltage across the first resistor, the second resistor and the temperature-sensitive resistance.
15. The circuit of claim 14 , further comprising a power control circuit configured to limit power consumption of the circuit.
16. A circuit comprising:
a first resistor configured to be coupled to a first terminal of a temperature-sensitive resistance;
a second resistor configured to be coupled to a second terminal of the temperature-sensitive resistance;
a temperature information circuit configured to:
receive a first voltage from the first terminal of the temperature-sensitive resistance;
receive a second voltage from the second terminal of the temperature-sensitive resistance; and
provide temperature information based on the first voltage and the second voltage, the temperature information circuit including:
a first analog-to-digital converter configured to determine a difference between the first voltage and the second voltage, and generate first digital information corresponding with the difference between the first voltage and the second voltage; and
a comparison circuit configured to compare the first digital information to second digital information, the second digital information corresponding with a reference voltage, an output of the comparison circuit corresponding with a temperature of the temperature-sensitive resistance.
17. The circuit of claim 16 , further comprising a reference circuit configured to provide the second digital information to the comparison circuit, the reference circuit including:
a band gap voltage generator; and
a second analog-to-digital converter coupled with the band gap voltage generator and the comparison circuit, the second analog-to-digital converter being configured to provide the second digital information to the comparison circuit based on an output voltage of the band gap voltage generator.
18. The circuit of claim 16 , further comprising a reference circuit configured to provide the second digital information to the comparison circuit, the reference circuit including:
a voltage follower circuit; and
a second analog-to-digital converter coupled with the voltage follower circuit and the comparison circuit, the second analog-to-digital converter being configured to provide the second digital information to the comparison circuit based on an output voltage of the voltage follower circuit.
19. The circuit of claim 16 further comprising:
a voltage follower coupled to a preset voltage, the voltage follower configured to provide a bias voltage across the first resistor, the second resistor and the temperature-sensitive resistance; and
a power control circuit configured to limit power consumption of the circuit.
20. The circuit of claim 16 , wherein the temperature-sensitive resistance includes at least one of a diode or a thermistor.