Temperature sensor circuit and semiconductor device including temperature sensor circuit

• US 10,001,414 B2
• Filed: 08/09/2016
• Issued: 06/19/2018
• Est. Priority Date: 05/02/2012
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun, Yamazaki, Shunpei
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): Cotey, Philip
• Application Number:
  US15/232,120
• Publication Number:
  US 20160349119A1
• Time in Patent Office: 679 Days
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence

Abstract

To provide a highly accurate temperature sensor circuit. The temperature sensor circuit includes a first constant current circuit; a first diode in which a first voltage reflecting the temperature of an object to be detected is generated between an anode and a cathode in accordance with a first current supplied from the first constant current circuit; a second constant current circuit; a second diode which includes an oxide semiconductor and in which a second voltage is generated between an anode and a cathode in accordance with a second current supplied from the second constant current circuit; and an amplifier circuit which amplifies a difference between the first voltage and the second voltage.

Claims

1. A temperature sensor circuit comprising:

a first constant voltage circuit;

a first semiconductor element where a first current flows between a pair of terminals in accordance with a first voltage applied from the first constant voltage circuit;

a first load where a second voltage is generated between terminals by supply of the first current;

a second constant voltage circuit;

a second semiconductor element where a second current flows between a pair of terminals in accordance with a third voltage applied from the second constant voltage circuit;

a second load where a fourth voltage is generated between terminals by supply of the second current; and

an amplifier circuit which amplifies a difference between the second voltage and the fourth voltage,

wherein a rate of change in the first current with a first temperature of the first semiconductor element is greater than a rate of change in the second current with a second temperature of the second semiconductor element,

wherein a value of the first temperature is same as a value of the second temperature,

wherein the second semiconductor element comprises an oxide semiconductor layer in a second channel formation region, and

wherein the first semiconductor element comprises a semiconductor layer other than an oxide semiconductor layer in a first channel formation region.

2. The temperature sensor circuit according to claim 1, wherein the oxide semiconductor comprises In, Ga, and Zn.

3. The temperature sensor circuit according to claim 1, wherein at least one of the first semiconductor element and the second semiconductor element is a diode.

4. The temperature sensor circuit according to claim 1, wherein a value of the third voltage is equal to or substantially equal to a value of the fourth voltage.

5. A semiconductor device comprising:

the temperature sensor circuit according to claim 1;

an output device; and

a signal processing circuit which controls operation of the output device using a signal.

6. A semiconductor device comprising:

a temperature sensor circuit which generates a signal;

an output device; and

a signal processing circuit which controls operation of the output device using the signal,

wherein the temperature sensor circuit comprises;

a first constant voltage circuit;

a first semiconductor element where a first current flows between a pair of terminals in accordance with a first voltage applied from the first constant voltage circuit;

a first load where a second voltage is generated between terminals by supply of the first current;

a second constant voltage circuit;

a second semiconductor element where a second current flows between a pair of terminals in accordance with a third voltage applied from the second constant voltage circuit;

a second load where a fourth voltage is generated between terminals by supply of the second current; and

an amplifier circuit which amplifies a difference between the second voltage and the fourth voltage, and

wherein a rate of change in the first current with a first temperature of the first semiconductor element is greater than a rate of change in the second current with a second temperature of the second semiconductor element,

wherein a value of the first temperature is same as a value of the second temperature,

wherein the second semiconductor element comprises an oxide semiconductor layer in a second channel formation region, and

wherein the first semiconductor element comprises a semiconductor layer other than an oxide semiconductor layer in a first channel formation region.

7. The semiconductor device according to claim 6, wherein the output device is a liquid crystal display device.

8. The semiconductor device according to claim 7, wherein each pixel of the liquid crystal display device includes a liquid crystal element, and

wherein the temperature depends on a temperature of a liquid crystal layer included in the liquid crystal element.

9. The semiconductor device according to claim 8, wherein the signal processing circuit is configured to adjust a voltage applied to the liquid crystal element using the signal to control operation of the output device.

10. The semiconductor device according to claim 6, wherein the oxide semiconductor comprises In, Ga, and Zn.

11. The semiconductor device according to claim 6, wherein at least one of the first semiconductor element and the second semiconductor element is a diode.

12. A semiconductor device comprising:

a temperature sensor circuit which generates a signal;

an output device; and

a signal processing circuit which controls operation of the output device using the signal,

wherein the temperature sensor circuit comprises;

a first constant voltage circuit;

a first semiconductor element where a first current flows between a pair of terminals in accordance with a first voltage applied from the first constant voltage circuit;

a first load where a second voltage is generated between terminals by supply of the first current;

a second constant voltage circuit;

a second semiconductor element where a second current flows between a pair of terminals in accordance with a third voltage applied from the second constant voltage circuit;

a second load where a fourth voltage is generated between terminals by supply of the second current; and

an amplifier circuit which amplifies a difference between the second voltage and the fourth voltage,

wherein a rate of change in the first current of the first semiconductor element is greater than a rate of change in the second current of the second semiconductor element,

wherein the second semiconductor element comprises an oxide semiconductor layer in a second channel formation region, and

wherein the first semiconductor element comprises a semiconductor layer other than an oxide semiconductor layer in a first channel formation region.

13. The semiconductor device according to claim 12, wherein the output device is a liquid crystal display device.

14. The semiconductor device according to claim 12, wherein the signal processing circuit is configured to adjust a voltage applied to a liquid crystal element using the signal to control operation of the output device.

15. The semiconductor device according to claim 12, wherein the oxide semiconductor comprises In, Ga, and Zn.

16. The semiconductor device according to claim 12, wherein at least one of the first semiconductor element and the second semiconductor element is a diode.