Circuit, sensor circuit, and semiconductor device using the sensor circuit

• US 8,836,555 B2
• Filed: 01/14/2013
• Issued: 09/16/2014
• Est. Priority Date: 01/18/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun, Yamazaki, Shunpei
• Primary Examiner(s): Mai, Lam T
• Application Number:
  US13/740,801
• Publication Number:
  US 20130181854A1
• Time in Patent Office: 610 Days
• Field of Search: 341118-168, 327/82, 327/91, 327/94, 327/355, 327/359, 327/361, 455/313, 455/323, 455/324, 455/325, 375/346, 375/361
• US Class Current: 341/122
• CPC Class Codes: G01D 3/028 mitigating undesired influences, e.g. temperature, pressure
• CPC Class Codes: G11C 27/026 associated with an amplifier G11C27/028 takes precedence
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/00 Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor H01L31/00 - H01L33/00, H10K10/00, H10N take precedence; details other than of semiconductor bodies or of electrodes thereof H01L23/00; devices consisting of a plurality of solid state components formed in or on a common substrate H01L27/00
• CPC Class Codes: H03M 1/124 Sampling or signal conditioning arrangements specially adapted for A/D converters

Abstract

A sensor circuit for obtaining physical quantities with a small margin of error even when the temperature varies is provided. The sensor circuit includes a sensor, a sampling circuit for obtaining a voltage value or a current value of a signal output from the sensor during a predetermined period and holding the value, and an analog-to-digital converter circuit for converting the held analog voltage value or current value into a digital value. The sampling circuit includes a switch for obtaining the voltage value or the current value and holding the value. The switch includes a transistor including an oxide semiconductor in a channel formation region.

Claims

1. A circuit comprising:

a sampling circuit including a switch; and

an analog-to-digital converter circuit,

wherein the sampling circuit is configured to obtain an analog value of a signal during a predetermined period and hold the analog value,

wherein the switch comprises a transistor including an oxide semiconductor, and

wherein the analog-to-digital converter circuit is configured to convert the analog value which is held by the sampling circuit into a digital value.

2. The circuit according to claim 1,

wherein the analog value is one of an analog voltage value and an analog current value.

3. The circuit according to claim 1,

wherein the oxide semiconductor includes at least one of In, Ga, and Zn.

4. The circuit according to claim 1,

wherein the sampling circuit further includes a capacitor element.

5. The circuit according to claim 1,

wherein an off-state current density of the transistor is less than or equal to 100 zA/μ

m.

18. The circuit according to claim 1,

wherein an off-state current of the transistor is lower than 1×

10<sup>−

13</sup> A when the transistor is 150°

C.

6. A sensor circuit comprising:

a sensor;

a sampling circuit including a switch; and

an analog-to-digital converter circuit,

wherein the sampling circuit is configured to obtain an analog value of a signal output from the sensor during a predetermined period and hold the analog value,

wherein the switch comprises a transistor including an oxide semiconductor, and

wherein the analog-to-digital converter circuit is configured to convert the analog value which is held by the sampling circuit into a digital value.

7. The sensor circuit according to claim 6,

wherein the analog value is one of an analog voltage value and an analog current value.

8. The sensor circuit according to claim 6,

wherein the oxide semiconductor includes at least one of In, Ga, and Zn.

9. The sensor circuit according to claim 6,

wherein the sampling circuit further includes a capacitor element.

10. The sensor circuit according to claim 6,

wherein an off-state current density of the transistor is less than or equal to 100 zA/μ

m.

11. The sensor circuit according to claim 6,

wherein the sensor is one of a temperature sensor, a magnetic sensor, a light sensor, a microphone, a strain gauge, a pressure sensor, and a gas sensor.

19. The sensor circuit according to claim 6,

wherein an off-state current of the transistor is lower than 1×

10<sup>−

13</sup> A when the transistor is 150°

C.

12. A sensor circuit comprising:

a sensor;

a sampling circuit including a switch; and

an analog-to-digital converter circuit,

wherein the sampling circuit is configured to obtain an analog value of a signal output from the sensor when the switch is in a conduction state,

wherein the sampling circuit is configured to hold the analog value when the switch is in a non-conduction state,

wherein the switch comprises a transistor including an oxide semiconductor, and

wherein the analog-to-digital converter circuit is configured to convert the analog value which is held by the sampling circuit into a digital value.

13. The sensor circuit according to claim 12,

wherein the analog value is one of an analog voltage value and an analog current value.

14. The sensor circuit according to claim 12,

wherein the oxide semiconductor includes at least one of In, Ga, and Zn.

15. The sensor circuit according to claim 12,

wherein the sampling circuit further includes a capacitor element.

16. The sensor circuit according to claim 12,

wherein an off-state current density of the transistor is less than or equal to 100 zA/μ

m.

17. The sensor circuit according to claim 12,

wherein the sensor is one of a temperature sensor, a magnetic sensor, a light sensor, a microphone, a strain gauge, a pressure sensor, and a gas sensor.

20. The sensor circuit according to claim 12,

wherein an off-state current of the transistor is lower than 1×

10<sup>−

13</sup> A when the transistor is 150°

C.